This paper explores various aspects of the Japanese sound system, including dialect divisions, languages in daily contact with Japanese, consonants, vowels, and pitch. It examines the historical records of dialects in Japan, highlighting the formation and characteristics of major dialects such as the Tokyo, Kansai, Hokkaido, and Kyushu dialects. The paper also discusses the influence of loanwords on the Japanese language, emphasizing the increasing presence of loanwords in daily communication. Furthermore, it analyzes the consonant and vowel phonemes in Japanese, paying attention to their variations and pronunciation differences, including the shape of the lips during vowel pronunciation and the pronunciation of special phonemes in Japanese, as well as the influence of the position of the tongue on the pronunciation of Japanese vowels. Lastly, the paper delves into the importance of pitch in Japanese, both phonetically and phonologically, and its role in word formation, meaning, and sentence-level intonation. By exploring these aspects, this paper provides a comprehensive understanding of the Japanese sound system and its significance in the language.