The Japanese language is a very hybrid language. Roughly half of words in Japanese originally come from Chinese (most kanji compounds). The Japanese have started importing words from European languages since they first came into contact with them. It started with the import of Portuguese words in the 16th century, then Dutch ones from the 17th to mid-19th century, as the Dutch were the only Westerners allowed to trade with Japan during most of the Edo period (1600-1868).
From the Meiji Restoration (1868), a great deal of German, English and French words entered the Japanese language. Sometimes words in these languages were quite similar, and a word like "virus", is even spelled the same in English, German, French or Latin, but has a different pronuciation in each language. Because this word was imported both from Latin and German, it was rendered in Japanese as ウイルス and ビールス, not following the English pronuciation (ヴァイラス).
That is good to know, as native English speakers often have trouble understanding "Katakana English", because Japanese sometimes alter the original pronuciation (well, most words actually), shorten the word (eg. "remokon" for "remote control") or change its original meaning (eg "maibu-mu" from "my boom" means something "trendy").
That may lead English-speakers to think that all katakana words that do not sound like in English are mistranslations. In many cases, they just do no come from English at all. Some were deformed from their original language anyway (ズボン from French "jupon").
Interestingly, some foreign words have acquired a kanji spelling since their adoption (eg. tempura 天麩羅, kan 缶).
Here is a list of imported words in Japanese that do not come from English. Chinese words are of course excluded (too many of them).
From Portuguese
てんぷら（also spelled 天麩羅)
タバコ (also spelled 煙草), from "tabaco"
金平糖 from "confeito"
合羽 from "capa"
クリスト from "Christo"
パン from "pan"
ボタン from "botao"
オランダ from "Olanda"
イギリス from "Inglez"
ミイラ from "mirra"
サンバ from "samba"
From Dutch
ランドセル from "ransel"
カン (also spelled 缶) from "kan"
ビール from "bier"
コーヒー from "koffie"
アルコール from "alcohol"
メス from "mes"
ペンキ from "pek"
オルゴール from "orgel"
ゴム from "gom"
ガラス from "glass" (only used for the material, otherwise グラス)
ニス from "vernis"
サテン from "satijn"
ホック from "hoek"
コルク from "kurk"
アルカリ from "alkali"
モルモット from "marmot"
カトリック from "katholick"
ベルギー from "Belgie"
From German
ビールス from "Virus"
ワクチン from "Vakzin"
アレルギー from "Allergie"
エネルギー from "Energie"
ホルモン from "Hormon"
クレゾール from "Kresol"
ギプス from "Gips"
レントゲン from "Roentgen"
ノイローゼ from "Neurose"
カルテ from "Karte"
リュックサック from "Rucksack"
メトロノーム from "Metronom"
カフェイン from "Kaffein"
ニコチン from "Nicotine"
ナフタリン from "Naphthalin"
アルバイト from "Arbeit", which just means "work"
ゲレンデ from "Gelaende"
ゼッケン from "Zeichen"
テーマ from "Thema"
タクト from "Taktstock"
From Russian
イクラ from "ikra"
ノルマ rfom "norma"
インテリ from "intelligentsiya"
ペチカ deom "pechka"
From Spanish
マリファナ from "marijuana"
ゲリラ from "guerilla"
カナリア from "canaria"
フラメンコ from "flamenco"
サルサ from "salsa"
ルンバ from "rumba"
タンゴ from "tango"
From French
(センチ)メートル from "(centi)metre"
アンケート from "enquete"
クーデター from "coup d'etat"
ズボン from "jupon", which means "briefs or skirt" in French, but "trousers" (BrE)/"pants" (AmE) in Japanese.
