title_body: In what ways are grammatical genders useful? In a previous question about making a language easy to learn as a second language I suggested that grammatical genders have very little usefulness. A couple of people, however, suggested that grammatical genders have more usefulness than I think. Because of this I am interested in hearing about any potential uses for grammatical genders.
  
  Usefulness can be identified by looking at what happens when the grammatical gender is removed. If the speaker needs to communicate the lost information through other means then the grammatical gender is deemed useful.
upvoted_answer: The generic term for genders is "word classes". In some languages male/female isn't the main way to divide up the world.
  
  Word classes are useful for co-ordination. If a language lacks gender, (or animacy, what have you), then you need some other way to know what adjective goes with what noun, which antecedent a pronoun refers to and so on. A language with lousy coordination might be English, with things like "He saw him hit him with it."
  
  They make languages hard for language learners because the semantic relationship between the word classes overtime becomes increasingly arbitrary and creates a lexical burden for language learners, i.e. you just have to memorize the word class for each word. Also, gender marker is obligatory, so you have a high entry cost-- you can't say anything until you work out the genders of the relevant words.