DS started half-day pre-K last week and will be in full day Kindergarten next year. He's going to be in a dual immersion language program to learn Spanish at elementary school, and this year is in a Spanish language pre-K to give him a head start in the language department for Kindergarten. Our school district is amazing, top 5% in the state, and the dual immersion kids test higher than the rest of the school and are fully bilingual, written and verbal, by 5th grade, so it seems like a great opportunity for DS. Full day kindergarten is the only option for the dual immersion program, so that's what he'll be getting.
He has not been around a lot of Spanish before, so it's really full immersion for him right now. He seems to be loving it! He came home the other night and could count to 10 in Spanish, and sang me a song as well. I asked if he could understand everything and he says, "oh, yeah, of course Mommy!" When I arrived at the end of the day, the teacher was asking everyone to put away their things and line up (of course all in Spanish) and he followed right along, and said, "Adios! Buenos dias!" as we left.
In just under two weeks, and a year younger, he's gotten a lot out of it, so I can imagine that a well run kindergarten would do fine with half days.