对牛弹琴的英文：
[Literal Meaning]
to/bull/play/string instrument
to play the lute for a bull

[解释]
用来形容说话的人不看对象

[Explanation]
to speak cant to a layman

[例子]
你和他谈文学等于对牛弹琴，他感兴趣的只有数学公式。

[Example]
To talk about literature with him is equal to speak cant to a layman. What he is interested in is only mathematical formulae.

[英语等价词]
to cast pearls before swine

An nod is as good as a wink to a Blind horse
对牛弹琴

Talk to a brick wall
对牛弹琴

Play the lute to a cow;preach to deaf ears
对牛弹琴

Futility: playing a harp before a Buffalo
"对牛弹琴,徒劳无功."

Jokes are lost on him.
对他讲笑话是对牛弹琴。

Don't explain it to him; it's only playing the lute to a cow
别向他解释，那只是对牛弹琴。

It's a pity that the majority of this earnest and tireless instruction all amounts to playing the lute to a cow .
可惜，大多数的谆谆教导都是对牛弹琴。

Do not cast your pearls before swine
莫把珍珠丢猪前;莫对牛弹琴

Their hints about his behaviour were(like)water off a duck's back.
他们示意他举止不当,如同对牛弹琴.

With this customer, he felt himself, as it were, casting pearls Before swine.
面对这个客商，他感到好像是在对牛弹琴。