This app can speak the various languages text.
The following is the supported language.

Arabic
Czech
Danish
German
Greek language
English (South Africa, Australia, America, Ireland, UK)
Spanish (Mexico, Spain)
Finnish
French (Canada, France)
Hindi
Hungarian
Indonesian
Italian
Japanese
Korean
Dutch (Belgium, Netherlands)
Norwegian
Polish
Portuguese (Brazilian, Portuguese)
Romanian
Russian
Slovak
Swedish
Thai
Turkish
Chinese (Hong Kong, Taiwan, China)
Hebrew

*** Addition of Pronunciations
It can do from "Settings"
General > Accessibility > Speech > Pronunciations

*** Addition of Voices
It can do from "Settings"
General > Accessibility > Speech > Voices

*** Attention
It seems that the voice may change when you change the language of the device or update iOS.
In that case, try setting the Language of iTextSpeaker's each text again.