The teenage midfielder turned pro with West Ham last week.
Lletget told whufc.com: "The American style of play is very different than the style of play in any other country. Spain, for example, is known for the technical side, whereas Americans are known for their athleticism.
"For me, though, my favourite player was the US midfielder Claudio Reyna, because he brought a different style to the game and I can relate to that.
"With my Italian heritage, Giuseppe Rossi is the player I look up to most because he has come from a similar background to me, and is also a similar-type player. It's my aim to make a name for myself like he has.
"My heart is in America, though, so if the chance ever arose to play for the United States, I'd love that."