speech synthesis – API or Open Source Solution to pronounce words in English

Any translation programs will do something for you.

Try iTranslate for iPhone

or iTranslate for Android

I have used the Android one, I believe that iPhone one is similar.

• You can pretend you are translating say from English to Chinese.
• Type an English word
• Press the speaker icon next to the English text

Disclaimer, I am not associated with either of them. I have u