When Japanese doesn’t have its own word for something it can use one of its two phonetic alphabets to represent a word from another language.
computer konpyu-ta コンピュータ
But as Japanese has a limited range of sounds, some loanwords (such as those with a “v” or “w” sound) don’t bear much resemblance to the original.
virus uirusu ウイルス
Other loanwords are tricky to revert back into their original language as the Japanese phonetic alphabets do not distinguish between certain sounds (such as “l” and “r”).
ラク raku/laku rack? lack?
Not all loanwords come from English.
アルバイト arubaito arbeit (German “to work”), “a part time job”
And sometimes, the loanword has parted ways with the meaning of the original word.
コンデンサー kondensa- capacitor (not “condenser”)
So although the phonetic alphabets can reveal the identity of a foreign word, they can also conceal it.