sql - Query error, column ambiguos -

the query produces error message. why case? may done correct query?

select name, date letter, language, city language = lang_id , place_sent = city_id ; 

error:

query not executed : 1052: column 'language' in clause ambiguous

so languauge column present in more 1 table . hence need clarify table want pick column from.. please add table name in where clause

select letter.name, letter.date letter , language, city letter.language = language.lang_id , letter.place_sent = city.city_id ;