I have many experiences with my clients or people whom I had interacted during their commissioning of IVR system, that they give least importance to the scripting as well as voice prompt. Most of the times, they discuss and emphasis on number of simultaneous calls, integration of the IVR with some CRM ( customer resource management) system or some other interesting IVR feature as well as its future expansion as well as maintenance. Nothing wrong for emphasizing on these aspects of IVR system, but after commissioning of the IVR, they have started changing the script as well as voice prompts many times over!

Many of clients have started out with TTS ( Text To Speech ) generated voice prompts and later ended up recording voice prompts by different artists in a studio! I have also seen some call center owner as well as some companies deploying voice recorded in office by some female staff using a PC and MIC, and putting the IVR into production. Invariably, they changed the voice prompts to studio recorded voice prompts from professional artists after one month or so!

While in some cases use of TTS ( Text To Speech) is inevitable or a must ( like retrieving dynamic data from database and playing them out), but there is no reason to use TTS or TTS generated voice prompts fixed menus, numerals as well as fixed names!

I would always advise people to use professionally recorded voice prompts in any IVR in production environment. While use of TTS generated voice prompts during testing and development phase makes sense, but in production, TTS should be avoided. Here are few reasons why one must use professionally recorded voice prompts only :-

1. Voice prompt is the only interface to the caller

In IVR system, voice prompts are the only direct interface with the telephone caller and telephone caller has no means to know about other aspects of the IVR system. A caller to an IVR system is not bothered about the technology behind the IVR system, or use of API ( Application Programming Interface) based on latest web technologies to fetch the required information for the caller at the back end. The caller is just bother about his required information and how quickly he could access it and how easily he could listen and understand without having to press any key to listen again!

2. Professional Voice Prompts gives seriousness to the IVR system

For many call center as well as customer service and support, IVR is the one which picks calls from every caller including the irate and fed-up callers! Professional, clear and pleasant voice ( I avoid using the word female) may have good effect on the caller and it may give indication to him what he may expect from the call! Unprofessional and difficult to understand voice prompts may scare away the caller or make him more non-cooperating irate customer!

3. Voice Prompts may make IVR caller experience pleasant

A clear and pleasant voice with understandable accent as well as pronunciation will surely increase user experience as well as satisfaction of the caller! A person may call to the IVR from a noisy background area and that will compound his problems in understanding IVR voice prompts or menu options if TTS generated machine prompts are used.

A professional voice prompt provider will always make the voice prompt in proper volume, speed, pitch as well as pronunciation which are a must for any production grade IVR system.

So, in order to improve usability and caller satisfaction, one should use services from a professional voice prompt provider, or at least use voice prompts recorded in studio by professional voice over artist.

Few days ago, I had posted about using IVR ( Interactive Voice Response) System in mission critical operation in underground mining operation. Continuing int he same line, there is another interesting IVR application which is useful in our day to day life and can prove to be life saving at times! That is IVR based automatic pill reminder service.

In short, automatic Pill reminder service is essentially an outbound IVR which is capable of dialing out programmed phone number of the patient at programmed time automatically without any manual intervention. When the call is connected, it will play a recorded message and then wait for confirmation whether the patient has taken the medicine or not. When the patient dos not respond the call or confirm the medicine taken, IVR will raise an alarm either by sending an email or SMS to medical staff responsible for the patient’s hospital so that some manual intervention can be taken immediately depending on the severity of the timely medicine!

This kind of automatic pill reminder service can be hosted or on premise IVR system. In India, Niche Tech Services (P) Ltd offers both on premise as well as hosted IVR based automatic pill reminder service.

Few essentials in pill reminder services are :-

1. It should support different language for different patients

The IVR should be able to play messages in different languages so that save IVR system could be used to alert many patients.

2. It should be be able to record response from patient

The pill reminder service should be able to accept some response either DTMF ( Dual Tone Multi Frequency) press or automatic speech recognition. Automatic Speech recognition ( ASR ) may work well since it will just need YES or NO response from the patient.

3. It should provide alarms

The IVR should be capable of raising an alarm to concerned doctor or medical supervisor responsible for the patient immediately if the patient fails to respond to the pill reminding call or respond about the medicine taken in negative. Timely intervention by a medical supervisor may prove to be life saving exercise at times.

4. It should have MIS

The system should be able to provide patient wise, call wise MIS ( management information system) so that complete medical history for the patient could be organised. It should also store all responses by the patient.

Having IVR based pill reminder system offers many benefits. For example, now a days everybody keeps a mobile phone with him all the time and always attentive to any call. So, alert system using a telephonic call has more chances of being attended.

Getting response and storing them is useful information for he doctor for analysing about the patient responsiveness to the treatment.

Using phone is one of the cheapest and better option that having any web based reminder system or alarm system. An IVR can precisely play a message about the type of medicine the patient is required to take at that time. This will help the patient to concentrate on his regular works having to remember about his medicines and worry about it all the time.

So, if you have a hospital or medical service facility, it is time you put automatic IVR based pill reminder system in place to serve your patients better! Even call centers can offer this service to many large hospitals and health care industries.

Internet offers many services which are useful in our day to day life. There are many web portals which providing directory services which list traders, shops, local business houses, various service providers etc. along with with easy ‘search and find’ option.

Web Directory Service IVR

There are few challenges for maintaining a directory service portal with accurate information. For example :-

1. Many directory service web portals still list phone numbers which are no longer in service or disconnected for may business houses. These phone numbers need to be periodically checked and verified. Or before listing them, one needs to verify it. When outdated phone number is listed against any shop or service providers ina directory listing website, it loses confidence in web visitors.

2. Address verification is another tedious and manual process which takes a lot of resources of the web portal. By providing accurate address, a directory web portal increases reputation among web visitors and gain popularity.

3. Many directory services allow web visitors or local business establishments to list themselves on the web portal. The phone numbers, addresses provided by them needs to be verified before publishing them. It is tedious and time consuming process.

IVR ( Interactive Voice Response) System can automate all the above verification process and can easily verify all the data.

How IVR can help directory services ?

1. IVR can make automatic outbound calls against any phone number listed against any address or business establishment. It can dial out the number and report back if the number is not reachable. If it is land-line number and does not ring, gets disconnected immediately or does not get busy tone after trying three times, it can safely assume that, the number does not work or exist and stop it getting published on the website.
When the phone number rings and picked up, then it can announce purpose of calling and then verify his address by asking him to press few keys!

This process can be completely automatic and can be done periodically to keep phone numbers updated and accurate.

2. In order to verify correct information or address, IVR can dial out the phone number, read out address using TTS ( Text To Speech) and then ask the called party to press a key to verify. IVR can also transfer the call to some human agent in case further assistance is required. With accurate address, the web portal can increase its credibility and respect by web visitors.

3. For user submitted data ( where web visitors are allowed to submit their shop, services to be listed in the web directory), IVR can be used quite effectively to validate phone numbers, verify address without manual intervention. While user submitted data can help a web directory portal grow, but these kind of data seem to be most inaccurate. With use of IVR, the accuracy of user submitted data can be improved.

Apart from IVR for verifying data, another important IVR application, Click To Call can be used to track leads generated by its listing, as well as allow added facility for web visitors to speak to these listings free of cost!

If you own a web directory service, yellow pages, it is time to augment your effort using IVR system!

IVR system is not just a clubbing together of state of the art CTI boards, high end servers, very easy to drag and drop tool design IVR call flow for flexibility. One of the saddest part about IVR development is, the users may not appreciate about these technological break-through like SS7, ISUP, CPA ( Call Progress Analysis), accuracy and speed of speech recognition or the or intricacies involved in detecting disconnect tone, engage tone.

They simply care about what menus they hear and if the options they press or speak works! They are least bothered about the hard work some one may have put in to detect her key presses, or recognise heavily accented English numerals, but only if the IVR retrieves the information it promised in its menu. The appreciate only when they can understand the information read out to her listening first time without having to press a key to listen again!

It may not be possible to satisfy all the users of an IVR system, but by using well scripted menus in simple language and intelligently constructed sentences may surely help majority of the people to use IVR system without having to learn the IVR before using it.

The answer to all these problems faced by IVR users and making IVR more useful and user friendly is ‘scripting of the IVR menus’! Script writing for IVR means, writing the IVR menu options in simplest language, well formed sentence so that the listener understands the message accurately without having to concentrate.

IVR scripting can be used in three areas to improve IVR usability:-

1. Scripting the menus
2. Dividing complex menus to simple sub menus
3. Scripting the phrases used for providing information

1. Scripting the Menus

This is quite straight forward. The menu options where IVR gives some options to the IVR user to either press telephone keys, or speak some word or phrase, should be properly scripted. Accuracy of the options is of course a must and forgone conclusion. For example, if the menu says, “To transfer your call to a customer care executive, please press 9″, then on pressing 9 by the caller, the IVR should transfer the call to customer care executive, not to the main menu!

2. Dividing complex menus

Script writers will divide complex options or large options will divide into some groups, and make it two level menus, in place of one. This will not only help first time callers, but also make it more user friendly faster with using ‘cut through’ key pressing!

3. Scripting phrases

Now a days, IVR has to retrieve many information from various locations through either database look up or by using API. Also, it may have retrieve information in bits and pieces from different servers, then knit them together, and then finally produce a sentence which would present a complete required message/information to the IVR user! Now that may not be easy for an IVR engineer! So, one must use a professional script writer for writing these phrases either to be recorded or used with TTS.

Without proper scripts used in IVR menus and in information, IVR will not be usable at all, even by expert IVR users! It will be very frustrating for users and all the great technologies used to design and develop IVR system will completely go waste!

Recently, I have started getting mails about asking open source IVR as well as its availability for free, download-able from internet! Most of the people who have asked me about “‘Open Source IVR” have heard about Asterisk. Before going into the details about Asterisk, being open source IVR, I would like to clarify few things about IVR ( Interactive Voice Response)  System.

IVR system consists of  four components, one can say. They are :-

1. CTI ( Computer Telephony) board
2. Call Flow development as per requirement
3. Voice prompts, TTS ( Text To Speech) Engine  and ASR (Automatic Speech Recognition) Engine
4. Host PC or Server for #1 through #3 above.

1. CTI ( Computer Telephony) board

CTI board is a hardware and I m quite sure, nobody will make it ‘open source’ or free for anyone! The other alternative is SIP ( Session Initiated Protocol) on VoIP ( Voice Over Internet Protocol). But for connecting to PSTN ( Public Switched Network), TDM based CTI Board is a must and there is no alternative, as of now!

All CTI boards come with their own set of API ( Application Programming Interfaces) to control telecom protocols and call handling. Dialogic, the biggest CTI company provides many APIs as well as sample codes in three major operating systems, Windows, Linux and MAC OS. Likewise, other CTI vendors too provide their proprietary C++ API for at least two OS.

2. Call Flow development as per requirement

There are many online as well as offline call flow development tools. Some Call Flow development tools are completely pictorial visual tool where one can drag and drop various call flow like components to make a call flow. Some others use simple ‘English’ like/natural language like scripts to define call flow. Incidentally, all these tools are free to use for developing the call flow, but to execute these call flow, one has to pay per port licenses.

VXML is standard call flow development language adopted by W3 which uses HTML like simple syntax. Presently this requires a third party interpreter which again requires per port licenses.

3. Voice prompts, TTS ( Text To Speech) Engine and ASR (Automatic Speech Recognition) Engine

Voice prompts are normally recorded in a studio by professional artists. One can also record voice prompts using computer/laptop and MIC for development purpose. There are many open source, freely available TTS. Even MS SAPI is freely available. eSpeak, a popular TTS which has support for many languages from all around the world, is an open source TTS which works well both in Windows and Linux.
Likewise there are many open source ASR that works well after refinements.

Now, major challenge is to integrate all these components and build a reliable IVR system. Now a days, IVR is no longer simple call flow of yes and no by the caller, but complex system with data retrieving from multiple sources. It performs complex task as well compute input data by caller, make a decision and respond to caller with appropriate answer.

Most of the time, making an informed choice of IVR which is most suitable for a particular IVR application is quite difficult.

Now finally, Asterisk is a truly open source telephony system with IVR facility. It is Linux based and supports many CTI hardware and many developers contributing to it. It is a completely DIY ( Do It Yourself) IVR platform. It may not be easy to develop an IVR system quickly for a beginner using Asterisk from a scratch. At the end, it may be as difficult as building IVR using native API available with CTI board itself.

Many high density and widely deployed CTI hardware are not supported by Asterisk. This is one disadvantage which Asterisk will take some time to overcome. And at the end, while some one tries to customise Asterisk, he might end up with his own proprietary piece of codes, specific to some CTI hardware only!

Advantage of using API of CTI board is the freedom of choice of operating system as well as programming language. Programming languages like C++ offer power of ‘real programming’ language to complete complex tasks as well as integrate with any third party software.

So, one may not have much choice as Open Source IVR!

Recently, I have been able to test VBVoice 5.6.2 using Dialogic D300 springware board as well as HMP 3.0. Mr. Sean from Pronexus has been kind enough to configure and give us a presentation to quick start developing voice application.

VBVoice IVR Toolkit : Power to Programmer

VBVoice is one of the most powerful IVR toolkit which is available in Microsoft .NET Integrated Development Environment as simple controls/components to develop powerful CTI application/IVR Software with any kind of computational need in the back ground. Any .NET developers using either VB .NET, C# can use its “CTI Building Blocks” to start building any kind of IVR system with complex call flow. This is one tool which has no limitation on computational capabilities except the limitation of .NET environment itself or programming skill! One need not worry about implementing smart features of any IVR Software DTMF, ASR, TTS, VBVoice has all features built into it.

We prepared two different machines with Windows XP OS, one each for Dialogic D300 springware board and HMP 3.0. And we installed required Dialogic System Release 6.0 for D300 board and HMP 3.0 as well as VBVoice 5.6.2. Mr. Sean from Pronexus had remotely activated license for VBVoice.

First we configured Dialogic HMP Software an activated four channel licenses for VoIP calls. Once it was done, we opened Microsoft Visual Studio 2005 C# project and loaded some VBVoice sample application. And it worked in single click! We used X-Lite installed in different computer on the same LAN to make voice calls.

After that we wanted to check with TDM board (Dialogic D300) in other machine. Since we had already activated VBVoice license on other machine with HMP, we needed to access the same license from this machine with TDM board through LAN. It was a simple configuration.

Once the license was done, we created a simple Inbound IVR to select Language on DTMF keypress using Microsoft Visual Studio 2005. It was done in less than five minutes and we could make calls to our PRI number and select languages.

VBVoice has both GUI tool for editing and configuring its various options like License settings, Telephony Interface type etc. For advanced users, one can simply edit the configuration text file quickly. Depending on the active licenses, all the controls, components gets loaded in .NET IDE, ready to be used! Any call flow can be created visually by dragging these controls and dropping on the design form. After that, one may simply configure the required DTMF keys, point to next menu options etc. All finer details like number of DTMF digits to accept, total delay time etc. are available for configuration on each control/component. After creating and setting the properties of these components, component’s events allow using code ( C#, VB .NET) to customize further the behaviour of the components at runtime depending on user input or any other external event.

VBVoice : Powerful IVR Toolkit

One of the interesting feature of VBVoice is Worker thread. It allows programmer to create separate thread for doing some computation separately without holding the main IVR Call Flow thread. For example, the Worker thread may try to access remote database server, access API, do some computation, billing etc. before giving feedback to main IVR call Flow thread.

To learn about more features one may visit Pronexus : VBVoice – IVR ToolKit.

We have been able to develop a few IVR applications in response to inquiries from our clients to give them POC (proof of Concept) about our IVR capabilities using VBVoice in very short period of time and could impress them suitably.

It also provides controls to dynamically create list of voice files from pre-recorded WAV files without using TTS which is played for menu selection. This kind of intelligent dynamic menu has been forte of C++ developers till now.

Like any other great products, VBVoice has one drawback, presently it supports only Dialogic boards. It does not support Sangoma or other cheaper cousins of Dialogic.

According to Pronexus representative, roadmap of VBVoice includes support for H.263 video play using Dialogic HMP and running VoIP in virtual machines. It will be available for testing very soon. So, we may be able to develop IVVR (Interactive Video and Voice Response System) pretty soon using VBVoice! In the age of 3G and IPad, VBVoice is going to provide exciting time for IVR developers!

In order to get evaluation version of VBVoice : one may contact me or Pronexus Directly : Get VBVoice or Write to Mr. Steve Brown, V.P. Sales at: steve.brown@pronexus.com.

IVR (Interactive Voice Response) system can do many things and one of the most common task it performs is “Call Transfer”. Both inbound and outbound IVR may transfer the active call to some other telephone number or human agent once the IVR user chooses.

Though in a call center environment, human agent may get information about the caller in a POP UP window in its desktop PC, but when call is transferred to any telephone number, this kind of POP UP window with caller information may not be available! But, IVR may surely do a “Value Added Call Transfer” by announcing caller details in voice! It may even offer the transferee the option reject or divert to voice mail, transfer to another telephone number! In PBX terminology, it is called Call Whisper or Call Screening and when IVR implements it, we may surely call it “Value Added Call Transfer”.

How to Implement Value Added Call Transfer :

Implementing value added call transfer with IVR is quite, may be simple extension of any existing call transfer. It can be implemented using both analog and digital CTI card. While implementing value added call transfer, “bridged call transfer” would be employed using two channels.

in Analog CTI :
1. Put active call “ON HOLD” by implementing flash key ( ON HOOK for certain duration, 200ms or so, depending of PBX used).

2. Dial out the transferee number. Play the previous incoming call details as soon as call is picked. Wait for DTMF key from the transferee if required.

3. ON HOOK the call. The previous incoming call which was ON HOLD would be connected now. This feature may be PBX dependent.

in Digital CTI Card:

1. Play call waiting message or music for the incoming call, say on CH1.

2. Use CH2 to make outgoing call to the transferee and when the call is picked, play call details which is active on CH1. CH1 may play message about the status of CH2 call.

3. When transferee on CH2 chooses to pick the incoming call, bridge CH1 with CH2.

4. When transferee chooses Voice Mail, CH1 will stop call waiting message, asks caller to record his voice mail as the transferee had chosen to get message in voice mail, and disconnect CH2.

5. When transferee chooses to transfer to anther call, disconnect CH2, use it to dial the new transferee number and repeat #2 through #5.

This is not PBX dependent as it uses two separate channels.

Benefits

Call whisper has many benefits. It offers the called party knowing who is calling, not only his caller ID, but other useful information like if he is an existing customer, new customer, name, services used by him. All these information, prior to answering his call not only increases efficiency of customer service, but also reduce cost for the organisation.

Value Added Call Transfer may allow intelligent routing of calls on “informed decision” as transferee may transfer the call again after knowing the caller details besides caller id.

Advantages of implementing using IVR

While some PBX systems offer Call Whispering facility, but implementing it with IVR software has many advantages. IVR software can compute, present more information about the caller.

Changing voice prompts, use of dynamic information using TTS, ASR are possible with IVR software.

So, value added call transfer in IVR system may increase better and faster customer service. Click to Call service combined with value added call transfer would be a ‘killer application’ which would surely benefit website owners to convert their website visitor to customer!

Like any other computer software, IVR too work inputs of responses provided by the user. Though, a computer application software has widely used input devices like keyboard, mouse, voice, even hand movement, IVR applications have limited, only two types of inputs or responses. One is telephone keypad which has 12 keys and automatic speech recognition!

Another specific difference between a normal computer application software and a IVR software is, IVR can provide the options sequentially in voice while computer application software can software options in various menus, buttons, drop down menu, quick links using related graphics etc. So IVR provides its options or tasks it can perform to a caller in series of voice announcement along with key option to press or word, phrase to speak for choosing the tasks. This is known as IVR menu.

With advent of hosted IVR services, IVR application has become designing of this menu system only, while the integration of CTI hardware with various PBX systems have become standard modules provided by hosted IVR service provider.

Irrespective of direction of call of the IVR ( inbound IVR or outbound IVR), menu starts as soon as the call is picked up. Normally, IVR starts with a “welcome prompt” typically welcoming the caller with greetings and quick short brief about the service, organisation behind the IVR.

IVR menus can be divided into two types depending on how user give commands to IVR application or how user responds to its menu options, DTMF(DualTone Multiple Frequency) or Telephone driven and ASR (Automatic Speech Recognition) driven. Both have advantage and disadvantages and are widely used. ( Click here for more about DTMF driven menu or ASR driven menu)

Apart from above two types of IVR menus, it can also be divided another two types depending on how menu options are generated.

1. Menu options can be recorded using a voice artist in studio and played back.
2. Menu options can be generated using TTS (Text to Speech) converters.

Again, choices in a menu, may be static or dynamic. When the choices in a menu are fixed for the IVR system, than the menu can be called as static menu while if the menu options changes dynamically depending on caller id, time of the day etc., than the menu can be called dynamic. For example:-

In a call center IVR, if a registered customer dials, he may be given different options while an unregistered customer would be presented a different options in the IVR menu.

Many people do not like TTS generated menus as one can make out the difference between human voice and TTS generated voice, specially in India, it has mainly to do with accent of the voice. TTS can be very useful in dynamic menu as well as presenting data retrieved from database where playing recorded voice may not be possible all the time.

Usability of an IVR depends mainly on the design of IVR menu. For more about usability one may check this : Usability of IVR systems.

An IVR user is interacts with IVR through it menu only. So it is very important to design IVR menu which is easily understandable to first time callers. Previously people used Visio like tools to design IVR menu. But now a days, almost all IVR development tools come with powerful, feature rich visual IVR menu designer giving DYI(Do It Yourself) feature for IVR customers.

What is TTS ( Text to Speech) ?
TTS or Text To Speech is a process where text is converted to WAV file and played back. So it is a system or often called “engine” that converts text to voice. If some one types a sentence in a note pad, a TTS software would convert it to voice ad play it through speaker attached to computer or laptop.

What does IVR System do ?
IVR System plays recorded voice on a telephone when a caller calls in. So, it is obvious that instead of playing recorded voice, IVR can play text file using TTS engine.

TTS software or engine:-
There are many TTS engines available. Many TTS engines are built in computer operating system. Microsoft SAPI5.1 is such TTS engine which is available for Windows Operating System. Voiceover is built-in TTS engine for MAC OS Leopard. There are various companies which make TTS engines. For example : AT&T, Nuance, SVOX etc.

Using TTS with IVR System
TTS is very useful when there are lot of dynamic content to be provided to caller in a voice portal. The use of TTS in IVR system is quite easy! Every TTS engine comes with SDK (Software Development Kit) which can be used to integrate with IVR application developed in various tools. Almost all RAD Tools for developing IVR applications, support TTS as well as speech recognition.

TTS produces voices which can be recognised easily that it is generated by a computer, not by human. So, people who are used to listening to human voice, may not be able to understand TTS easily. It is specially true for people whose first language is not English. Most of the world’s TTS engines support English. Recently many companies are developing TTS for other languages as well.

It may take some time, but it is expected that quality of TTS voice will increase where everyone will be able to understand TTS Engine generated voice easily. That will help voice portals immensely.

VUI ( Voice User Interface) is the call flow of IVR system. Usability of IVR is dependent on the VUI. So it is desirable that considerable amount of time be devoted in designing, testing and documenting VUI of IVR system before actually developing IVR system.

Here are few simple VUI design guidelines of tips I have thought of :

1. Identify specific purpose of IVR system
First step towards designing VUI should be the question, why would a caller call the IVR system and how quickly efficiently IVR should reply to his “why”. If the purpose of an IVR system is to record customer complaint, allow customer to lodge their complaint in the first menu itself. IVR should not try to act very smart or human by asking intelligent questions and get the caller answer before it actually is able to lodge the complaint. The other way is to allow the caller lodge the complaint, provide him complaint ticket and then ask few polite questions about details of the his complaint an which is completely optional. IVR system should stick to its specific purpose in its operation.

2. Maximum 3 Levels of menu
Stick to maximum 3 levels of menus before caller gets his desired information after calling a IVR system. A caller should not be “interviewed” or put through “set of question answer session” till he gets the desired information. In many IVR system, it is observed that, trying to be smart, caller is put through set of questions, many irrelevant options before actually providing the information required by the caller. So, golden rule should be, provide maximum 3 levels of menu, before a caller is answered or provided the final information.

3. Provide Shortcuts as per usage
IVR system should have in-built MIS (Management Information System) to enable finding out the most used menus and information. Depending on the usage, shortcut should be provided to access the widely used menus quickly. Many repeat caller will not like to go through the same menu and having to choose same options before his desired menu options. Even a first time caller may like to use the shortcut once the shortcut is explained.

4. Top Level Menu options
By top Level Menu options, I mean the menu options provided to caller as soon as his call is answered. This is the menu which is to be designed very carefully and success of IVR system may depend on this menu to a large extent. This menu should not be long list of options, but few main specific purposes of the IVR system. And this menu should be changed as per usage statistics. For example, if the 4th option here has less usage than 3rd option of the second level option of 1st top level option, than most probably, it is time to bring the second level option to top level menu. If the IVR system is a call center and human agent is available, then I strongly suggest that option should be given to caller in Top Level menu to speak to a human agent.

5. Voice prompts
Voice scripts should be simple English or the language the IVR is using. The language should be really simple and easy to understand, without any grammatical errors. It should be spoken as if you are speaking in daily conversation with regular pauses. A good menu design may look totally ridiculous if proper scripting and voice prompts are not used.

There are five VUI design tips I have been using in all my IVR works. VUI is a must for IVR usability.