Here´s a tough question. Which languages - modern or ancient and let´s say a set of 10-15 - would you study to get a complete understanding of what human langues can be and can do? To get an overview over the inner workings of and possibilities of human languages? My interest here is purely in understanding what LANGUAGE is and can be - not in numbers of speakers (major/minor languages), in difficulties of studying or pronouncing etc.
my list would at least start with these:
- sanskrit (for its mathematical precision)
- turkish (for a highly logical grammar in a modern language)
- english (for immense productivity of its lexis)
- italian (for its musicality)
- thai (as a tonal language)