Thai spoken language vs written language 

That's correct. You can divide it into two parts: writing and reading, and speaking. When it comes to writing, you can write เนี่ย, and when you read it, you can say เนี่ย with a falling tone without adding any emotions. However, when you speak, you have the freedom to express emotions and feelings. By making it a low tone, you create a concise and abrupt sound, which conveys surprise and seriousness. 😀

Oh, I didn't realize that. I've listened to it again, and I think it might be a result of sound distortion. When we speak quickly, the sounds in words can sometimes get distorted, as you can hear in the video. My intention was to say 'ไม่รู้ (mâi róo), but when speaking fast, it may sound like แมะรู้ (máe-róo) unintentionally. Sometimes, the sound might be weakened or even changed to another, like มะรู้ (má-róo). It's normal when we speak fast. I had two of my sisters listen to it without providing details. When I asked them what I said in the video, they replied, 'คุณไม่รู้หรือ (khun mâi róo rǔe),' and they didn't realize that I said แมะรู้ (máe-róo). I believe they understood the context and that the sound แมะ (máe) represents the word ไม่ (mâi).

no need to pester this guy with an invitation to join a sect