Strikes are fairly common in Bolivia. When I was in Cochabamba two year ago my host brother had a lot of "vacation" because of extended strikes during year, mostly because the government would periodically stop paying teachers - especially in rural areas, and the urban teachers would strike in solidarity or for other reasons such as not being provided school supplies. But the current strike by the urban teacher's union is much more interesting. Evo Morales' government is trying to make the teaching of indigenous languages compulsory in primary schools (read about various other problems facing Morales in this Washington Post article). From what I've read in the Bolivian papers, the teachers are complaining that such a policy will put non-indigenous students at a disadvantage and that the government didn't consult with the union. The central government started having bilingual instruction (after decades of Spanish-only teaching in indigenous communities) in the mid-1990s, but the idea of teaching non-Indians indigenous languages is likely too much for some Bolivians, particularly the elite sector.
The fight over language instruction is another front in the battle for Bolivia's identity. Last night, a prominent peasant leader from Evo's party was almost killed in a fight over the ongoing constituent assembly, where the question of ethnic identity is a big point of conflict. Evo promised to place more value on indigenous cultures, which obviously got a lot of support during the election in a country where indigenous people make up 60 percent of the population. It will be interesting to see if the teacher's union will have to back down if the people support the new education policy. It's not clear that indigenous people actually support bilingual education, for the same reasons that immigrants in this country don't always support it - parents want their kids to be successful, and learning the language of power quickly is the best way to go about that.