What would Japanese look like if Chinese characters were not introduced to Japan?

Japanese itself has a small number of phonemes (consonants, vowels and semi-consonants), and ancient Japanese syllables are all paired with a consonant and a vowel. Just look at the five-tone chart, including the deleted sounds, there are only more than 40 syllables. Without the influence of Chinese, there would not be even four special sounds: difficult sound, long sound, plucking sound and promoting sound. With the development of culture, new words have to become very long, so we can refer to Hawaiian and other Oceania languages. A large vocabulary affects the efficiency of daily communication, so the speed of speech will become faster. Among the common languages, the fastest languages are Spanish and Japanese, and the similarities are that there are many syllables, the consonant vowels are close to one to one, and the information density is low (each syllable provides less information on average). Chinese is the slowest because of its high information density. If civilization develops to a more mature stage and the vocabulary of a language reaches a certain level, there must be a way to shorten it. For example, the long word collapse mentioned in the high-vote answer is to omit some syllables, which will have many ambiguities in the case of large vocabulary; Discarding some phonemes can produce a small number of new syllables, such as Manchu Tungusic, losing ending vowels and appearing consonant ending syllables; Discarding or adding phonemes can form complex consonants and vowels and form a large number of new syllables, such as Micronesia in Oceania; Or there is a tone system, and the number of syllables suddenly increases, such as Chinese. Without the influence of Chinese characters, pseudonyms would not be like this. If it is spontaneously formed, it is possible to invent many hieroglyphs for simple recording, and then use these hieroglyphs to express sounds. It's probably still syllable writing, that is, each syllable has a separate symbol, not phoneme writing (consonants and vowels are written separately). In addition, without the influence of Chinese, the pronunciation of words will not be divided into pronunciation and training.