Is it true that Americans pronounce the S in CLOTHS as has a TH sound and hard to follows Informal American English?

That's not quite accurate. It's not that the "S" is pronounced with a "TH" sound, but rather that the "TH" sound at the end of "CLOTH" is often pronounced as an "S" in American English.

Here's why:

* Sound Simplification: In casual speech, Americans often simplify consonant clusters at the end of words. The "TH" sound is complex to produce, so it's easier to replace it with the simpler "S" sound.

* Regional Variation: This pronunciation is more common in certain regions of the United States, particularly in the South and Midwest.

* Formal vs. Informal: You're more likely to hear the "S" pronunciation in informal settings and casual conversations. In formal settings, like a news broadcast or a speech, the "TH" sound is more likely to be used.

So, while the "S" pronunciation is common, it's not a hard-and-fast rule and doesn't necessarily represent all of American English.

Keep in mind:

* It's not considered incorrect: The "S" pronunciation is simply a common variation in American English.

* Context matters: The pronunciation of the "TH" sound can depend on the speaker, the context of the conversation, and the region they are from.