This article is about dual language programs generally and mixes some of the different types. One-way immersion is a type of DL program for students of a native language, usually Spanish, learning a target language, English. They can sometimes start out as 90% native and 10% target moving to 50% each by fourth grade. Two-way immersion DL programs have native English and native Spanish speakers. They are usually always 50-50 the whole time.
Currently, LISD has one-way 50-50 DL programs at Independence, Central
and Peters Colony. Next year, they are offering two-way 50-50 DL programs at 8 elementary schools. In addition, they will offer a one-way immersion program at Wellington with English as the native language and Spanish as the target language. I believe they are all voluntary.
The linguistic reseach supporting DL over English immersion for academic success seems pretty solid. I wonder though whether LISD has dedicated enough resources to help deal with the logistical burden it will create for parents (who likely won't be able to help with or check half of the homework) and for teachers (who now have to have twice as many report cards to review, twice as many parent teacher conferences, etc.)