How to fix poor TTS pronunciation - Discussion

Is there a way to change the pronunciation of "toll road" from "congestion charge"? :p
What voice have you selected? The English_US voices (Susan or Samantha, depending upon the model) say 'toll road'
I have the Irish male voice (which cuts through my radio/podcast voices very well). He uses "congestion charge" for the French toll roads.
I don't have the American voices, but English Jane says "toll road". Both Irish voices say "congestion charge" ( testing all over same route on French toll roads ).
With the disconnected GPS, I turned it ON and heard a strange bongo sound at startup.
Funny, I could've sworn it was a tomtom. :D

I hear it once in a blue moon. Most of the time, not.
These tweaks have most certainly improved pronunciation for my TT.

I also find that the TTS does good in an area corresponding to its language. "Susan" in area with english street names , and "Charlotte" in area with mostly french names, but both are absolutely horrible at converting the other language.

When you get in areas where the street names are a fairly equal mix of french and english names (I am in the west part of montreal), it is so bad that it is becoming intolerable pretty quick.

Found the best option not to have to change the language setting all the time is to leave it at "english us" and use a French recorded voice when I am local (and for my wife :p) , just switch back to "Computer voice susan" when in an english area to recover the full features.

It is quickly done and since recorded voice do not process street names then there is nothing to change in options or impacts on the menus

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I must have missed something because that would be !!!

Have they used the exact same abbreviation for saint and street in the maps such that there is no way differentiate in the lex file?

Cant beleive they cannot agree with the provider of their files to have twist to it (st- for saint or else)

But as I said' i must have missed something as "Susan" was telling me "Street Andrew Street" today.

But as I said' i must have missed something as "Susan" was telling me "Street Andrew Street" today.

You'd have to rename the street in mapshare to "Saint Andrew St". The cspeech.dat file is responsible for setting streets such this to "Saint Andrew Street."

When you remove the cspeech file, you remove all the hints, including some helpful ones like this.
Many entries in the lex file had a different format, for the most part they were causing me issues.

only one I cannot understand are the following, anyone has an idea of what they are: cds , ech and rdpt

"cds" = "\f@-kh-`u:-l-HTh-HEh-s-`Aa:-kh"
"ech" = "\f@-E-$-Aa:-n-$-`Oa:-Hr-Hr"
"rdpt" = "\f@-Hr-`Oa:-n-ph-w-`E-n"

"cds" = "\f@-kh-`u:-l-HTh-HEh-s-`Aa:-kh"
"ech" = "\f@-E-$-Aa:-n-$-`Oa:-Hr-Hr"
"rdpt" = "\f@-Hr-`Oa:-n-ph-w-`E-n"

cds = Cul de Sac
ech = I'd swear this says "Asian Shore"
rdpt = I dunno

See my personal cheat sheet, attached file, for future reference:


  • Loquendo Phonemes.txt
    961 bytes · Views: 449
cds = Cul de Sac
ech = I'd swear this says "Asian Shore"
rdpt = I dunno

See my personal cheat sheet, attached file, for future reference:

Huge thks for : Loquendo Phonemes.txt it allowed me to find what they are

ech is echangeur (french for interchange), and
rdpt is rond-point (french for traffic circle)

Yeah, the "ech" was a bit of a giveaway regarding language, but you've caught me with my parlez vous pants down -- afraid my alternate languages cover only the Cyrillic alphabet :eek:.
Can someone please talk me through how to do this with a Via 160.
Where/how do you get into the Map folder, for example?
Lacks airport in Los Ann-hell-ez?

The biggest problems I'm still experiencing on my GO 740 is that LAX airport is "lacks airport" and Los Angeles is "Los Ann-hell-ez."

I've tried putting things in the ".lex" file, to no avail--like:

"lax" = "\f@-El-HEI-kh-x"

I've tried different things for "Los Angeles," but the funny thing is, TT pronounces "East Los Angeles" correctly!

Does anybody have any other ideas?

BTW, renaming the "cphoneme.dat" file causes other pronunciation problems, so that's not a good option.
new person question

After many many hours, I figured out a workaround for the poor TTS on most Tomtom devices.

It impacts all devices that use Loquendo (except maybe the really old GO 910). It does not impact devices that use Vocalizer (ONE-XLS from 2007, ONE 125S, ONE130S, XL325S, XL330S, and iPhone).

To fix TTS, go to your map folder (usually "North America" or "Usa_Canada_and_Mexico") and look for the file cphoneme.dat. Rename this file cphoneme.old.

After that most of your TTS will be fine. If there are any words that are still mispronounced, you can fix them by using notepad to edit the following files:
- \LoquendoTTS\data\roadnrEnglishUS.lex (all models except the GO 720/920)
- \LoquendoTTS\EnglishUs\roadnr.EnglishUs6.8.lex (for the GO 720/920)

Thanks to misterbk, canderson, and malouff for all the additional background research that helped me isolate this fix.

cphoneme.dat is the Teleatlas hint file, that processes localized hints before the Loquendo hint file processes. The problem is that the cphoneme.dat file appears to be using special characters that Loquendo doesn't understand. Many times when words are pulled from cphoneme, the Loquendo error log says it cannot interpret them. Further, when this interpretation error happens, Tomtom stops looking at the roadnrEnglish and EnglishUS.dbl hint files. Loquendo does a great job on its own pronouncing these words without Teleatlas's assistance, as evidenced by the demo at

I hope this helps others, I tested it through a variety of problem roads ("Boston", "San Francisco", etc).

A silly question perhaps but how can I access the North American map on my GO 2505 in order to follow the above directions? The GO2505 does not show up as a drive when connected to my computer via usb cable the way my digital camera does. Thank you for your patience.
Not a silly question at all..........

You can't access the file system on that model since, as you say, it does not show up as an external drive on your computer.

So, you can't make alterations to files such as the ones noted in this thread. Nor can you do much of anything else, such as make a user backup .....:eek:
DHN, Thank you for the info. Do firmware updates apply to the GO2505? Additionally, I cannot make the voice recognition software recognize a single word I say. City, address, etc. I don't have a strong regional accent or speech impairment. Do the 2505's have an issue here? I'm from Toronto as well.
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If there is a firmware application update, you should be notified as such by seeing an icon on your MyHome notification icon, either a vertical yellow bar (think that's for a new Home build) or a down arrow coloured green.

Try something simple with the voice command like 'navigate Home' or 'clear route' and see if that's recognized.

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