Characters with radical "口" are usually related to a human mouth or its functions, and this radical is often placed on the left side of a character (though it can also appear as an upper or lower component of a character).
口 只 句 可 台 史 右 吃 各 合 命 咸 后 司 哥 同 周 商 名 向 否 售 喜 告 员 号 另 哭 叫 叶 呀 呢 吗 吧 啊 喂 哪 听 吵 吸 味 唱 呼 和 喝 咖 啡 啤 咱 咳 嗽 响 嘴