Accumulative describes something that grows little by little as more is added over time — a pile that keeps getting higher. Harm from smoking can be accumulative; interest on a debt can be accumulative; a child’s English can be accumulative if they keep a little more each week. It is a formal, rather uncommon adjective. In everyday English, people much more often say cumulative for the same idea. Though actually, some writers keep a small difference: cumulative for the total you get when you add things up, accumulative for the habit or process of gathering. Many careful speakers do not bother with that split, and cumulative still wins in ordinary talk.

累積的