I heard this last week on a conference call.

Problem:
The speaker pluralized the wrong word.

Explanation:
Someone made a comment during a conference call.

The call’s facilitator responded to the comment by saying, “I have two train of thoughts on that.”

Given that “two” modifies “train” and not “thought”, the word “train” — not the word “thought” — should have been pluralized.

This type of mistake is a common English blunder in spoken American English because avoiding it requires one to think quickly beyond the common pattern of putting the pluralizing S or E-S at the very end of a concept, which in this case is “train of thought”.

Another example of this type of mistake is pluralizing “attorney general” by saying the incorrect phrase “attorney generals” instead of the correct phrase “attorneys general”.

Solution:
“I have two trains of thought on that.”