The development of a completely new programming language and of an entire programming environment is a very ambitious and comprehensive goal that cannot be accomplished by two people in a reasonable amount of time. So contributions of all kinds are not only highly welcome but simply indispensable.
Lava is an Open Source project. You can get the most recent Lava sources through the CVS service of the SourceForge Open Source Mediator. (CVS stands for "Concurrent Versions System".) For more details see the LavaPE project summary page at SourceForge.
See here for contributions that are particularly desirable from our present point of view.