I am writing nearly all of it / everything in my SECOND LANGUAGE. I'm glad you're here / in my life!
Difficult to get right without seeing the general style. Choose between 'everything' and 'all of it' according to context, use the latter if something specific is referred to. Put SECOND LANGUAGE in ITALICS but NOT CAPS to indicate that these are the writer's use of loanwords.
The second sentence as I have given it, is a sort of dynamic equivalent. The literal meaning is, 'Thank you because you're there,' so you might prefer grateful to glad, but I'd think it's probably over the top - too ponderous. (it would sit well in Wuthering Heights!) You might prefer 'there' to 'here', too, it's a matter of taste. The English 'there' insists on a bit of distance which I don't feel is implied in the Danish, it's just a way of putting it, a bit shy, perhaps, of admitting to being close, affectionate or indebted. 'In my life' on the other hand is perhaps too intimate - again, I cannot judge from the isolated quote. If you wish, you're welcome to e-mail me (see profile) with the context. By interpretation you might understand, 'It's good to know you' or even, 'I owe you one,' but they're VERY far from the literal meaning and I'd only consider those if the style demanded it.