You can use Google Now with our Android app to add tasks using a voice command as described here: https://todoist.com/blog/2013/11/todoist-for-android-adds-support-for-google-now-and-dashclock/
If you're referring to adding voice notes (recorded content in an audio file), we may consider adding such option in the future and you're welcome to request it in our Votebox: https://todoist.com/Vote/
The problem is that it does not work if the phone language is other than English - "note to" is not recognized as a command.
That's unfortunately Google's limitation. Google Now is supported only in some languages and language settings, but won't work in others. We're sure it will be improved by Google in the future, though.
Thanks for reply - in this case maybe it would be worth adding your own - built in - recording mode, without having to use a “code word” to start recording for Todoist, or to think of some other word or command that would be more international – perhaps “todoist” itself ?
That's not possible. When you say "Note to self" on a phone set to English, our app has nothing to do with this, it's Google's software that recognizes this as a supported command and triggers a certain function. This is the exact same function for every language that Google supports. We don't have a direct option to "hack" Google's voice recognition software to force it to trigger the same function when you say a different word. This all happens on Google's end. We can only add the option that once this command is triggered, you can add the text you say after that into Todoist, among other apps.
Voice recognition is an extremely complex technology made possible with sophisticated software so we can only utilize the functionality Google has at their disposal and "hook up" Todoist as an app where you can add the text if the certain command (defined by Google) is triggered.
Now, aside from that, you will have an option to record voice notes and add them as regular notes to Todoist's tasks (from within Todoist). This will be available in version 4.0 soon, but that's different from the global commands that Google supports.
OK, thanks for information.