(This question toes the line between belonging here and belonging on the Retrocomputing Stack Exchange.)
Here is the quote; sometimes the first sentence is omitted:
The most important thing in a programming language is the name. A language will not succeed without a good name. I have recently invented a very good name, and now I am looking for a suitable language.
It is always attributed to Donald Knuth. Some instances date it to 1967.
What is the original source? I can't find it anywhere. The earliest reference I can find online is in a manifest for a programming languages course from 2000. Even if the ultimate source is not a published document, but rather a statement in a conversation or in some other form that was not recorded, we should expect earlier references, especially if the quote really is from 1967.