死語しご
shigo

Noun

1. dead language; extinct language

Antonym of 活語
しかし、その一方いっぽう、ラテンはそのときまでに「死語しご」となっていた。
shikashi sono ippō ratengowa sono tokimadeni"shigo"to natte ita.
But, then again, Latin was already a "dead language" by that time.
Noun

2. obsolete word; dated word; word that has become passé

Related to 廃語
それって死語しごじゃないの。
sorette shigojanaino.
People don't say that anymore.