We booked a double room.

Doublet is an important concept in linguistics.

I overslept today, so I was late.

He accepted the proposal without dispute.

I want to learn about the history of Jūnishi.

A diphthong refers to the phenomenon where two vowels are pronounced consecutively within a single syllable.

My account is protected by 2-step authentication.

He is doing a special exercise to train his digastric muscle.

When learning Japanese grammar, it is important to understand the verbs of the second conjugation.

He made a model of a dodecahedron.