The Lao script was originally used as an abugida (consonants have implied vowels) for the Lao language, just as most of the writing systems related to it.
The Lao script is now used as an alphabet for the Lao language. There are now ways to spell all vowels and there are no implied vowels.
Apparently these changes were the result of a series of language/script reforms which also included removing many letters (which have still not been added to Unicode). The last reform was by the communist Pathet Lao after they took control of the country.
Some of this may be wrong. I'm looking for detailed sources on how many reforms they were, when each reform occured, and what the specific changes of each were.
An Internet source in English would be best but French, Lao, or Russian might exist too. I'm also interested in finding a dictionary using any of the former spellings.