The Japanese culture and language are innately intertwined and inseparable from one another. In order to speak the language correctly, it is necessary to learn about Japanese culture. However because the culture is so distinct and there are so many aspects which are difficult for foreigners to understand, it often times seems shrouded in mystery.
By breaking down various aspects of culture and studying them individually, we can gain insight into the culture as a whole and how the language is spoken correctly.
East vs. West
One major hurdle to overcome in understanding Japanese culture is the concept of humility. Humility by Japanese people is not only shown by various forms of politeness in speech, but it is also shown on a daily basis by various types of bowing (in addition to other reasons such as apologizing and showing gratitude). Even though humility can be interpreted as weakness in western cultures, it is seen as a virtue in eastern cultures, and boasting a sign of weakness. Hiding your true strength from the enemy was seen as more of an effective form of strategy in battle and business as it carried the element of surprise.
Hide Your Talons
Some years ago, I remember seeing a conversation between a foreigner and a Japanese person. The Japanese man asked the foreigner if he could speak Japanese; to which the foreigner replied in Japanese, “yes, but that is only because I studied the language in school.” This statement sounds innocent enough, but it is something a Japanese person would never say.
It would be much more appropriate to brush the compliment off with a phrase such as “いいえ、そんなことないです” (no, not at all) or “いいえ、とんでもないです” or とんでもありません (a simple “thank you” would suffice as well but is generally less preferred of the two). Japanese people refer to humility as “謙虚” (けんきょ) and anyone who tries to draw attention to their accomplishments or shows pride in any of their achievements is looked down upon as being arrogant. There is a common idiom in Japan, “能ある鷹は爪を隠す”（のうあるたかはつめをかくす）. It literally translates as “a capable hawk hides its talons”.
Humility and Modesty
In fact there are many things we often may say in English that Japanese people would never say. When talking about our family sometimes we say something such as “I have three beautiful daughters” or “I have been married to my lovely wife for 20 years.” If this were translated directly into Japanese it would not only be considered extremely strange but also very arrogant because Japanese people would think you are bragging that you have beautiful daughters, or that you have a lovely wife.
Though not used so much nowadays, Japanese people used to say 馬鹿息子 (ばかむすこ) which literally means “stupid son”. It does not necessarily mean that they really think their son is stupid (though this may be possible). It is said not only because is it frowned upon to say nice things about your family but it is actually better to sound like you are putting them down.
In western cultures we praise our spouse with statements such as “my better half”, Japanese people used to refer to their wives as “愚妻”（ぐさい）which translates to something like “my foolish wife”. If parents express their love by overly spoiling their children or seem to brag about their children, then people would sometimes call them “親ばか” (おやばか) literally meaning “stupid parents”.
There are numerous examples of how understanding Japanese culture is fundamental to speaking Japanese correctly, but understanding the degree to which humility and modesty play a vital role in Japanese culture is certainly a start.