They refer to the same product,
No they don't.
saying Ipod Touch or Itouch are these like two different devices by different companies
Yes, they are different devices by different companies.
The *iPod touch* is the
ONLY name of the product from Apple. It has never been referred to in any Apple literature as 'iTouch' ever.
The
iTouch is, in fact, a cheap, poor quality knock-off product which has copied the iPod touch in styling made by an Italian company called Pasen:
http://en.pasen.it/product_detail.php?id=23
I don't know why people would buy an *iPod touch* and then want to call it by the name of an inferior, rip-off product.
It'd be like buying original Levi jeans and then saying they're a cheap, fake brand from a market.
And strangely, people don't refer to the "iPod nano" as "iNano", the "iPod shuffle" as "iShuffle" or the "iPod classic" as "iClassic".