at the end of the dip lang are you like fluent fluent as in you could go an work in a professional environment in the other country and understand everyone and everything no worries or is it like you can say alot of useful sentences but arnt quite as free flowing as a fluent speaker
Depends on the language.
Try Chinese, and you won't get anywhere - it's a difficult language to learn.
Try Spanish, though, and you'd pretty much have most of the things down pat.
Check the below spoiler for a large infographic.
Spoiler
(http://dailyinfographic.com/wp-content/uploads/2011/05/Hard-Languages-To-Learn.png)
To elaborate from my experience..
Russian has a completely different grammar system to English. English focuses on using word order.
The dog attacked the cat
The cat attacked the dog
We get meaning from these sentences based on what came first in the sentence.
In Russian, it's a completely different system.
Firstly, all of the articles are dropped.
Dog Attacked Cat
Cat Attacked Dog.
Secondly, it doesn't matter where you put the word in the sentence - it matters how you conjugate and modify the word. It's the internal properties of the word which tell you how it behaves in the sentence. In this case, the blue text is meant to indicate that I've changed the spelling of the word "cat" in Russian to indicate it's relationship to the other words in the sentence - is it doing the attacking or is it being attacked?
Dog attacked cat
cat attacked Dog
^These mean the same thing in Russian, regardless of word order, because you change the properties of the words themselves (their pronunciation and spelling changes; the meaning is NOT dependent on the order of words in the sentence, unlike English).
This whole concept becomes very difficult in Russian, because to convey meaning, you need to fully grasp 6 different ways of conjugating words; known as "Cases". This is present in a lot of languages, like German, but Russian notably has 6 of them which makes things difficult; it's comparable to Latin.
Other languages like Chinese are Tonal, so the same word can mean four completely different things. Pronunciation and speaking is very different in Chinese, and to make yourself understood takes practice and time.
The below infographic explains the random phenomena of these languages. You can also google language syntax to understand a bit on how it works - maybe Linguistics could be a good breadth for you if you're interested in learning more languages. I know I find it fascinating.