Un pregunta o una pregunta???
This word is masculine or not???
Like idioma should be un idioma~~Muchas gracias~~I know some nouns they will have different meanings for its masculine and feminine
form...like el capital y la capital...but they're same in Eng...I mean capital in Eng also has 2 meaning...Entonces~~out of my curiosity...la mar y el mar.they are same or nor???

Question

Un pregunta o una pregunta???
This word is masculine or not???
Like idioma should be un idioma~~Muchas gracias~~I know some nouns they will have different meanings for its masculine and feminine
 form...like el capital y la capital...but they're same in Eng...I mean capital in Eng also has 2 meaning...Entonces~~out of my curiosity...la mar y el mar.they are same or nor???

Answer

una pregunta y un idioma= una lengua. -a is the marker for feminine in spanish, so most of the time sustantives ending in -a are femenine. exceptions are few. also some nouns allow for both genres: el mar/la mar. 
-o is usually a marker for masculine but be careful: you'll find in spoken "la moto" that is short for "la motocicleta".  Also words ending in consonant tend to be masculine. el tren, el ordenador, el avión. -e is ambiguous: el coche, la noche. problem is that gramatical genre has no logic: you can't look at a thing and ascertain if it is masculine or feminine, just must learn.

Answer

un idioma, una pregunta

Answer

"idioma"= masculine 
"pregunta" = feminine

this is a good source if you can open it: http://www.spanishdict.com