We use (yalla: يلا) when we want to say "let's go" in my Jordanian accent and I assume in other Arabic accents. Yet (hyya bina: هيا بنا) is used for "let's go" in Modern Standard Arabic (MSA).

يلا is more commonly in all Arab countries It's short for يالله it doesn't mean letterly (let's go) but we use it as (let's go) هيا بنا it's letterly mean (let's go) but it's not commonly now days because it's standerd Arabic يلا بنا : Egyptions use it like يلا بينا But if you use any of them they all make sence You don't have to use بنا or بينا, as long as you're using يلا يلا = yalla يالله = ya Allah or yaallah بنا = bena بينا = beena

It's Not يلا بنا in Egypt It's يلا بينا

يلا is used in most arabic dialect. هيا بنا is a Modern Standard Arabic ( Fusha) يلا بنا yalla Bena is more like Egypt dialect.

Sorry My mistake i meant literally instead of letterly