Is it possible to construct our own sentences using what little of the language that we know? What about foreign words, words that are not part of the native language? Like... computer, Jeremy, candy, etc.

Well on UESP there is 2 different sections, one for the dragon alphabet and another for the language.

http://www.uesp.net/wiki/Lore:Dragon_Alphabet This one shows what letters are in the dragon language

http://www.uesp.net/wiki/Lore:Dragon_Language This one shows words and what they are in the dragon language

Of course. The problem is that every time you say "Fire", well... you know... makes for an awkward party conversation.

This is great

And lo did my mighty Axe of Wrath cut through the soul of Alduin the Beast.

I spent a few minutes making that into my sig using UESP. I will probably change it soon to suit a new playstyle.

Yeah I don't think we can know words that aren't already stated, unless Bethesda ever releasies some kind of expanded list of Dragon language words.

It would be pretty hard to create a sentence from words not released.. my name itself, though it is meant to translate to 'The Elder Scrolls' directly translates to 'The Ancient Scrolls'.. but its the same thing, Kruziik most likely is both Elder and Ancient.. so if there is no direct translation to a word you want, just use one that loosley means the same thing, it more than likely IS the same thing..

On a side note, the UESP states that 'Kel' means 'Elder Scrolls'.. this is wrong, as in the Dragonborn poem it says 'Arkh Fin KEL Lost Podrah' which means 'And the SCROLLS have fortold, not the ELDER SCROLLS... just puttin' it out there ^^