There are many Japanese words that WK doesn’t teach directly (through vocab lessons), but by using them in the example sentences.
Today I learned 熟女 (じゅくじょ), which basically means MILF:
「コウイチが熟女好きっていう噂を聞いたんだけど。」「マジかよ!もしそれが本当なら、俺とコウイチに共通点ができるってことになるぜ。」
“I heard a rumor that Koichi likes older women.” “Seriously? If that was true it would mean that he and I have something in common.”
俺の隠れ家へようこそ。ビールは冷蔵庫に入ってるぜ。ちょっと不便かもしれねぇが、煙草は外で吸ってくれよな。
Welcome to my man cave. Beers are in the refrigerator. It may be a bit inconvenient for you, but you’ve got to go outside to smoke.
Not directly from the example sentence but I did learn today that Chicago’s “Hard to Say I’m Sorry” is 「素直にならなくて」 in Japanese.
It seems that translating song titles was more common in the past (I would say from the 60s to the 80s). Even so, it wasn’t done across the board.
For instance, Genesis’s The Lamb Lies Down on Broadway (1974) was 「 眩惑のブロードウェイ」. But all their album titles since 1980 has not been translated into Japanese (except to write them in katakana).
In the case of Black Sabbath, this transition to katakana happened in 1986, the Rolling Stones in 1983, KISS in 1984, King Crimson in 1974, etc.