Columbia defines "non-traditional student" as someone who has interrupted their education for more than one year. If you only spent one year learning English and you're now applying to college, you'll apply to Columbia College or the School of Engineering and Applied Science. Plenty of students defer for a year after high school and are then a year older when they enter freshman year; it's really not that uncommon. Plenty of students also transfer to Columbia College from other schools, though I'm not sure how many both defer and transfer. Since you only took a year off, though, you're considered a "traditional student."
If you had taken two years off to learn English, or get a job, or join the military, or whatever, then you'd have to apply to the School of General Studies. According to their website (Columbia GS | School of General Studies | Columbia University in the City of New York
), the average age of a GS student is 29. GS students take the exact same classes as Columbia (and Barnard) students. Columbia is unique among the Ivies in having an undergraduate college that caters to non-traditional students, but also allows them to take all the same classes as younger undergrads. Other schools just offer (very good) extension programs and night classes.
So you should apply to CC or SEAS as a transfer student.