Special Case using articles (A, An, The) with liquids

[CaJeandMJ]

Hello I am a native English speaker; however my girlfriend is not, her native language is Croatian. She speaks and writes English pretty well, but she is studying for certain tests that require an extremely high proficiency in English. She is aware that words such 'a', 'an', and 'the" are articles and she is aware on how to properly use them. However she keeps getting a bit thrown off by liquids. For example she would say "I am going to go get a tea" or "I want a lemonade". While grammatically it fits how an article would function, to native english speakers this sounds wrong.

I told her that typically liquids are not labeled as singular objects but rather as singular objects inside of something IE "a cup of tea" or "a glass of lemonade".

I have looked around, but can not find a good definition of how to explain to her why this is, is there someone that is more knowledgeable about English speech that could explain it to her for me ?

[Josef Essberger]

She's probably learned (correctly) that while the indefinite article is not generally used for uncountable nouns such as liquids, we do indeed sometimes us them when we mean "a cup of" or "a glass of". So for example in a restaurant we might very well order "two teas and a coffee please".

See also: http://www.englishclub.com/grammar/noun ... able_3.htm