Text-to-Speech Engines
Text-to-speech (TTS) engines are programs designed to convert normal language text into speech. In this article, I will try to discuss the advantages and disadvantages to using TTS engines. At the bottom of the page you can find a list of free and commercial engines.
Note: It is important to understand that Text-to-Speech engines and voices are two different things that one requires the other to work correctly.
Quick way to find the correct pronunciation
Whatever language you're learning, you don't always know how to pronounce a word. It's especially true about the English language because it is known to be very illogical and inconsistent in its pronunciation rules (probably because there are so many accents and dialects of English).
So instead of guessing, it's a great idea to look the word up in a TTS engine.
Listening experience and understanding
To a degree, listing to a voice produced with a TTS engine can be as beneficial to a language learner as listening to a normal voice. Apart from that you can expand your experience and understanding by listening to any text at any speed
E-mails or articles
Most people use TTS engines to have their e-mails and some text read aloud. It is handy for people whose vision is impaired or for those who are just too lazy to read it themselves. People who study languages can benefit from a TTS engine reading an article a lot, too. However, here's a word of warning: this technique should never be used with free voices (more on that below).
Some voices may be a bit/very faulty
Unfortunately speech synthesis technology is still far from perfect. Especially if we're talking about the voices that you can download free of charge.
Free voices (but no only) usually have many flaws, such as unnatural intonation. Therefore, it is generally not recommended to use TTS engines too often, as they are likely to do more harm than good.
TTS engines and voice are not cheap
Prices are not low, although affordable. TTS engine called "TextAloud" can be bought for about $30 at NextUp.com. Voices cost similar amounts (Cepstral charges $29.99 a pop) but prices vary.
Free Text-to-Speech engines and voices
There are quite a few. As far as TTS engines go, I will now only list Speakonia. The easy-to-use graphical user interface (GUI) of Speakonia is similar to Notepad. Speakonia is compatible with free Microsoft voices that you can download below.
Microsoft Text-to-Speech Engines
Mary, Mike, Sam and More (7.3MB)
L&H TruVoice TTS Engines
American English (0.99MB)
British English (2.54MB)
Dutch (2.58MB)
French (2.24MB)
German (2.18MB)
Italian (1.97MB)
Japanese (3.00MB)
Korean (3.03MB)
Portuguese (2.39MB)
Russian (2.85MB)
Spanish (2.36MB)
Commercial Text-to-Speech engines:
NextUp - One of the best I've come across so far. You can get it for $29.95.
CoolSpeech - A decent piece of software with many features also priced $29.95.
Natural Readers - This easy to use software can convert any written text such as MS Word, Webpage, PDF files, and Emails into spoken words. NaturalReader can also convert any written text into audio files such as MP3 or WAV for your CD player or iPod. $39.50
Commercial HQ voices:
To summarize: using text-to-speech engine is a wonderful way to learn a foreign language. You can benefit from it by listening to single words or to entire articles. However, Text-to-Speech engines should be used with great caution as they are still imperfect. It's generally worth to invest some money if you can afford it.