Japanese is a language that leaves statements vague, sometimes leaving important key words out of the sentence, using ambiguous words, or abbreviating words or phrases.
This is done subconsciously, so Japanese do not know that it is extremely complicated trying to translate their sentences to another language because of its obscure sentences.
Historically, Japanese is known for their humbleness and honor/validity of spoken words, and it can be said that the language reflects their behavior; being straightforward is not humble and the nuance of words and context is meant to be left to the understanding of those having the conversation/discussion.
Japanese believed that spoken/written words would become reality and refrained from using direct and strong words for fear of the power the “word spirits” worked. For example, instead of using the word “death”, “passing”, “hiding”, “falling” (as in flower petals falling), were popular ambiguous words used.
Also, words used every day are sometimes abbreviations themselves.
Ohayo, or what is used as a greeting of “good morning” today, once was a lengthy greeting. After “ohayo” was supposed to be a context and small talk to convey how healthy it is to wake up early in the morning or pay respects to early risers.
However, in order to avoid and conflicts from the morning by saying the wrong thing and to maintain the greeting short, rest of the sentence after “ohayo” became open-ended.
So this means that “ohayo” is really not to greet how beautiful the morning is, but to express respect to early-risers which eventually became a simple word of morning greeting. It is a pity that the true meaning had been lost in time.
Leaving out words or abbreviation in the Japanese language characterizes the characteristic of Japanese and still is like a type of social code that Japanese have in agreement.