When you create a "matching" resource on textivate, it really does make a difference which side you put the target language...
TL = Target Language (the language being taught)
L1 = First language / mother tongue / the language of instruction.
Consider the activities generated by textivate when you create a resource based on 12 or more matching items (see image above). There are 32 (at the time of this blog post).
Let's go through them...