forget, noisy
諠 centers on two seemingly opposite ideas: forgetting and noisiness. The connection may be that noise can distract or cause one to forget, or that forgetting can lead to a noisy, chaotic state.
諠 combines 言 (speech) with 宣 (proclaim, announce). The exact historical development linking speech and proclamation to 'forget' and 'noisy' is uncertain; it may have originally referred to loud, distracting speech that causes forgetfulness.
Words (言) proclaimed (宣) loudly can be so noisy that they make you forget what you were thinking.
For ケン, imagine Ken (a friend) talking so loudly that you forget your own thoughts: Ken -> ケン, and his noisy speech makes you forget.