H i Rosetta Stone not much good for beginners tried it and found it difficult so gave it away , as it was a Pantipp Plaza copy . Much better and a lot easier , if you can get it is Robertsons Practical English Thai Dictionary , this has been out of print for some time and not available here in UK , but if you can find it buy it , it uses the phonetic system and the spellings are kept as simple as possible , authors description not mine , also it is pocket sized so can carry about with you .
The above covers speach only , never bothered with reading and it has never posed any problem .
Another program I have tried , they are a US company , is Languages of the World , but unfortunately as it is also speech recognition accents cause havoc , gave up on this luckily it was a library copy , no cost .