Speech intelligibility
Speech intelligibility refers to the 'understandability' of speech, and the ability to use speech to communicate effectively in everyday situations. It can be affected by many factors, including pronunciation accuracy, audibility and speaking rate.
The Speech Intelligibility Scorer uses speech recognition and text to speech technology to:
How the Speech Intelligibility Scorer works
To score your speech intelligibility, simply enter any text and read it out loud. As you speak, the recognised words are scored from 0 to 100 and highlighted in green. Any unrecognised words are highlighted in red. Once all of the words have been highlighted, the following results are displayed:
Speech intelligibility score
Speech intelligibility is a measure of how easily speech can be understood and is expressed as a percentage. The speech intelligibility scores are categorised as:
| Intelligibility description | Intelligibility score |
| Unintelligible | 0% |
| Poor | 10% - 30% |
| Fair | 30% - 50% |
| Good | 50% - 75% |
| Excellent | 75% - 100% |
Audibility
In order to understand speech it must be audible. Audibility depends on the loudness of speech and is measured in decibels (dB). The human hearing range goes from 0 dB to 120-140 dB:
| Condition | Audibility (dB) |
| Hearing threshold | 0 dB |
| Whisper | 30 dB |
| Normal conversation | 60 dB |
| Shout | 90 dB |
| Pain threshold | 120 -140 dB |
Speech rate
Speech rate is the term given to the speed at which we speak and is expressed as the number of words spoken per minute (WPM). Depending on the type of speech, the rate may vary from 100 WPM to over 400 WPM:
| Type of speech | Speech rate (WPM) |
| Slow speech | 100 - 110 WPM |
| Conversational speech | 120 - 200 WPM |
| Audiobooks and podcasts | 150 - 160 WPM |
| Auctioneers and commentators | 250 - 400 WPM |
Supported languages
The Speech Intelligibility Scorer uses the computer's default speech recognition engine. There are several speech engines available for Windows:
- US English
- UK English
- French
- Spanish
- German
- Japanese
- Traditional Chinese
- Simplified Chinese
If your preferred language is not installed, you can obtain additional languages by installing the appropriate Windows language pack.
Who should use the Speech Intelligibility Scorer?
The Speech Intelligibility Scorer is an invaluable tool for anyone interested in the production of speech. It can be used by speech and language therapists or by their patients wishing to practice between sessions. It can also be used as an aid to learning a foreign language.
System requirements
| Operating Systems | Windows 10, 8, 7 and Vista |
| CPU | Minimum 1 GHz Intel® Pentium® or equivalent |
| Memory | Minimum 1 GB of RAM |
| Storage | 100 MB of free hard disk space |
| Microphone | A USB headset microphone is recommended |
Download free trial
The Speech Intelligibility Scorer is now only available as part of the icSpeech Standard and Professional integrated applications.
To download a free trial of icSpeech Standard Edition, simply click on the download button and follow the installation instructions.
For best results, we recommend using a USB headset microphone. See our range of recommended microphones.
Buy online
On order completion, you will immediately receive:
- A secure download link to the latest product version.
- A product registration key.
- Priority technical support.
- Free product updates.
- A 30-day money back guarantee.
| Home user license |  |
| Commercial licensing |  |