|For that matter, isn't Latin the same way? |I wouldn't be surprised if Italian and |Spanish and others got it from Latin. Mother tongue[spanish] => 'Lengua Materna' Mother tongue[latin] => "Lingua Mater" Language[spanish] => Lenguaje Language[latin]=> Linguarum All of this are valid expressions | Of course, in German and English, we have | the concept ("language"==="speaking organ") | though not the same root word as Italian | and others. Same for latin derived languages.... IDIOM=any expression that consists of at least two words, which is expressed differently in other language. So it seems Mother tongue is not an idiom ... In spanish we say ("Yo tengo frio") what is exactly translated as "I have cold" In english ("to pull his leg")what is idiomatic translated into spanish as "to take his hair" What is interesting to me is how 'idiomatic' meanings are created depending onthe 'value' of each of the words that it contains. 'Mother tongue' is many-languages valid expression because Mother and tongue have the same.... poetic (the best word I found) meaning in all languages (built-in words ) In contrast with to "to pull his leg" and "to take his hair" where the poetic meaning of hair and leg differs from the English culture and the Spanish culture due Spanish people tends to be bald and English people tends to be Taller so they lost easier the equilibrium.. ....I did not smoked anything wired mom !! IMO Same happens with programming lenguages....a lot to think about..(regexs, flow control) The best way to know a population is knowing its idioms. JP Sartre.