Since last year: Como utilizar

Hello friends!!
I need you to give me a hand with my doubt, maybe there's no sense in what I'm writing, however, here it goes!!!

When I use Present perfect I can never mention past time, and this structure comes always followed by certain adverbs or prepositions as: Since, already, just, ever, for, before:
My doubt is:
If I have a sentence like that: I have spoken English "since" "last year"
Must I take into account the adverb "since" or the past time " last year " ?
If I only say: "I spoke English since last year" , chances are this sentence is right?

Thanks in advance and sorry if I made any mistake, I'm an English teacher, and the most of the things I know I was taught by myself, I studied in an English course (Wizard) that helped me a lot too, but I've already finished it and I didn't have an enough explanation about some grammar points, I can get by, but it's intricate when I need to explain my students about some structures, mainly Present Perfect!!!

Have a nice week, my friends!!!!
I learn a lot from this site!!!