Lengua means tounge or mothertounge ..so when your are talking about you know a couple of languages or a language ,it is way better saying lengua than idioma.you need to practice more and more to get it perfectly .
Like when your are asking someone : how many languages do you know, it would be better to use lengua But when your are talking about like They speak 15-20 languages in this country ,would be better using idioma All u need is practicing more and more , nothing but that
Since posting this, I think I can answer my own question. It does appear that "one" in Spanish changes with gender. Lengua and idioma both mean language, but since lengua is used here and it is feminine, una is correct. However, if idioma were used (being masculine) then "un or uno" would be correct.
Just so you know, "uno" is always shortened to "un" before a masculine noun (or a feminine noun that begins with a stressed "a" or "ha"). However, if it's not directly before a masculine noun, it's "uno" - so it's "yo solo hablo un idioma" - I only speak one language, but "yo solo hablo uno" - I only speak one. With feminine nouns that don't begin with a stressed "a", it's always "una".
Thank you so much for your reply, the 'uno' was a typo in my post, my question was regarding the order of 'only'. Saying 'I only speak one language means I only speak it and not read or write whereas 'I speak only one language' means I don't speak other languages, which I think is the intent. Does this apply to Spanish in the same way?
I think this is spanish from southern america, right ? Is there a setting to learn to learn spanish from spain ? It's not the first time I realise that the words used are not those used in spain. Example : jugo instead of zumo, carro instead of coche... I live in Barcelona and it's annoying to not be sure that what i learn with the app is the proper "idioma" of the country I live in.