Point 6:  
The word  khy          

English ภาษาไทย
  The subjects I am taking
physics, chemistry,
  and English.
  วิชาที่ผมเรียน คือ ฟิสิกส์ เคมี
  The largest city in America
New York.
  เมืองใหญ่ที่สุดในอเมริกา คือ   
  The elder brother of my
  father or my mother is
  my elder uncle.
  พี่ชายของพ่อหรือแม่ผม คือ
  I am Mr. khăw.    ผม คือ นายแก้ว

The word
khy is commonly translated into English as "is, are", but its meaning is more specialized than that of its English equivalents. It means more specifically "is, are as follows" (first example above), "is by definition" (second and third example), or "is identical with" (last example). The term is commonly used in giving definitions or as the equivalent of our English terms "namely", "that is", "as follows".