The following languages are available in audio format:
Translated texts containing less than 20 characters are not downloadable as audio files.
The number of characters for the source language should not exceed 1200.
This corresponds roughly to 600 words, anything between 30 to 40 sentences or 4 paragraphs approximately.
By default, all translations are set to be formal translations.
Although informal translations are available with the API, the decision was made to use formal translation for all languages including German, French, Italian, Spanish, Dutch, Portuguese (both Brazil and Portugal) as well as Russian.
As a rule, sentences with markup (HTML, XML), in-text markup and tags should be avoided. All tags are parsed and removed.
An effort is made to keep the translated text as close as possible to the original structured content. That includes splitting on newlines and text outlined detection.
However, I cannot guarantee 100 % accuracy.