敬語 in Informal Situation

Question

I have noticed reading manga/light novel and speaking with friends that, despite talking in informal way, sometimes they use 敬語 (like ますand です) for one or two sentences, then switch back to informal speaking. There are a particular reasons why these kinds of things happen?

Answer 1

Generally speaking, this typically happens (almost unconsciously) when the speaker wants their statement to sound more formal, important, official, serious, dignified, and so on. For example, when:

• Talking about something serious (money, business, funeral, ...)
• Talking about something difficult
• Declaring/swearing something strongly and/or dignifiedly
  • Esp. Making a counterargument (e.g., 言いましたー！ "I did say it!")
• Their boss is nearby

If you still have trouble understanding your particular example, please share the concrete example sentences.

Also note that, depending on the relationship, mixture of keigo and plain form is not really uncommon, and I do this all the time when talking with my friends (see my answer in the first link below).

Related

• How do Japanese speakers transition from polite to plain form amongst friends?
• When speaking openly with a group of people, is it okay to speak casually with some and formally with others?
• What (if anything) does it typically mean when a native speaker switches from casual to keigo with you?