Assembly language is a programming language that talks fairly directly to the computer. Unlike machine language, which is what the computer understands, assembly language is mnemonic, so that it can be understood and remembered more easily by a human being; in fact, assembly language is really just machine language in mnemonic form.
Assembly languages are specific to a given CPU chip and are named after it (e.g., 8080 assembly language, 6809 assembly language etc.). They are harder to program than a high-level language, but they produce programs that are more efficient and run faster.
Unlike= ao contrário de, diferente de
Just= apenas, justamente
CPU= Central Processing Unit = Unidade Central de Processamento
Are named= recebem o nome
After it= de acordo com ele (chip)
Harder= mais trabalhosas
Run faster= rodam mais rápido