Error tolerance is the extent to which errors are tolerated.
Errors (slips) or non-standard dialect are generally tolerated in informal casual conversation (chatting) as long as they do not affect meaning and comprehension. At the other end of this spectrum, it is expected that formal prepared written texts, particularly academic written texts, should contain few, if any, errors.
Students may have different attitudes towards their own errors. Some hate making errors, while others don't care, but most are probably somewhere in the middle.