The normal term is speech community.
This has the advantage over "language community" in that it can be used for communities for which the common factor isn't that they all speak some language, but also for communities which speak a particular dialect, or even some minor language variation.
The term is used to focus on identifiable communities of people with shared behaviours. In a context where two languages are in contact, many speakers will be L1 speakers of one language and L2 speakers of the other. Categorising people by the languages they know and speak is not likely to be very productive because of the overlaps. Instead distinct speech communities can be identified based on the languages its members speak at home, in school, in the workplace, the languages they hear on TV etc.