As I understand this, you have two translation files, from english to hungarian and from english to italian(?). And what you want is to use english as key to combine the italian and hungarian one, correct?
My solution only works if you don't have many files to convert but where it is feasible to do the steps by hand.
It is important, that you check that the alternating languages pattern is true for every pair in both files.
At first, open both files in Notepadd++ and open Find/Replace by hitting CTRL-F or Edit->Find/Replace... Then click the replace-tab. Select the regular expression search method and enter the following for find:
With find next you can check if it is selecting two lines at once.
For replace enter:
Replace the cursor to the beginning of the file and try some clicks at "Find" and "Replace". It should write the words from to consecutive lines in one, separated with a space. Do this for both files, as mentioned. You now have the key values (if I understand the problem correctly) in both files in the first column. If the first column in both files now contain the exact same words in their respective lines you can continue. They should look like this:
You the that the first column is identical in both files. You now use the column mode (pressing alt while selecting anything from the second file). Select anything in the second file. Press CTRL-C (Edit-> copy). Open the first one, and insert so many spaces after the end of the first line that it exceeds the longest line in that file. Then add the contents from the second one by hitting CTRL-V. Should look like this:
white fehér white blanco
green zöld green verde
red piros red roja
Now you have to remove the keys by find/replace. Find:
^([^ ]*) ([^ ]*) *(.*) (.*)$
Should now look like:
Voila. Hope that helped!