los Idiomas o las idiomas
Idioma es la excepción.
Yo sé que es EL idioma
pero es
lOs idiomas
o
lAs idiomas
?
Gracias por tu ayuda 
5 Answers
Se dice "los idiomas"
El agua is different from el idioma.
Feminine nouns beginning with a stressed 'a' sound are preceded by el instead of la to avoid the conjunction of the two 'a' sounds.
El agua, las aguas
El águila, las águilas
El hache, las haches
The last is noteworthy and shows how it is not the sound, and not the spelling, which is the cause of this usage.
gracias 
y los aguas o las aguas?
There is a whole class of Spanish nouns ending in -ma that are masculine. So they are proceded by the definite articles El or Los. Their etymology is Greek. Examples include:
El programa
El idioma
El aroma
El clima
El enigma
El sistema
El etcetera...
Eddy is right ''los'' idiomas
When a noun has a masculine article eg el reloj = clock, el papel = paper or even feminine words with masculine articles (exceptions) eg (el) agua = water, (el) problema = problem o (el) día = day,** they still keep the same gender when changed to their plural form.**
eg; el reloj (the clock) -------> becomes los relojes (the clocks)
el hombre (= the man) -------> becomes los hombres (= the men)
el día (the day)-------> becomes los días (=the days)
Feminine nouns do the same:
la casa (the house)-------. becomes lascasas = the houses
and la camisa (the shirt) -------. becomes las camisas (the shirts)
I hope this helps to clarify things for you 
