Here is the sentence:
夫は涎らさんばかりの喜びようだ。
Her husband seems so happy he is almost drooling? That is, he is ecstatically happy? What is this? らさん
Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up.
Sign up to join this communityHere is the sentence:
夫は涎らさんばかりの喜びようだ。
Her husband seems so happy he is almost drooling? That is, he is ecstatically happy? What is this? らさん
夫は涎{た}らさんばかりの喜びようだ。
This is an example of bending the rules for a literary aesthetic.
The kanji 涎{よだれ} does not have the 垂{た}らす reading, but the meaning and unusual way the author wanted the reader to read it are clear. This is relatively common even without ふりがな in advanced novels. This usage let's the reader know the thing being 垂らすed is 涎 without having to say it.
垂らす becomes 垂らさん because it is a classical Japanese form that is still in use today. Another example is 溢{あふ}れんばかりの笑顔.