Whenever ん is before 'm', 'b', or 'p', it sounds like 'm'. If it comes before a 'k' or 'g' it's a bit more nasal, like a 'ng'. In the rest of the cases it's a regular 'n' sound. Other words you may have heard are がんばって and かんぱい which both follow the rule and make ん sound like 'm'
The problem arises from the fact that the sound being made does not truly exist in English. A person could spell it in roma-ji as tenpura and be correct. We just became used to spelling it as tempura in English and so that is what looks natural when reading the word.
It's the same with Chinese and English - trying to match the sound from a syllable/pictorial (syllabary) writing set to a character of an alphabet is going to cause... certain issues.
Exactly. In the case of ん, the pronunciation is /ɴ/, which is a uvular nasal consonant (non-existing in English). It is distinct from the consonants /n/ (which is an alveolar nasal) and /m/ (which is a bilabial nasal), having its point of articulation quite far from theirs. Apparently, though, its pronunciation may be realized differently in some contexts, as described in an article on Wikipedia:
> Japanese phonology - Moraic nasal
Probably at the time it was introduced to the world, of course the outside world didnt know about the changing sound, when they heard tenpura, they wrote it in a way they knew that it would match how it sounded as it was said by the native people. and it just passed on from time to time.
I hear the "n" and its spelled with an "n" in romaji in every Japanese lesson I've ever had in 7+ yrs so I'm not going to complicate life by introducibg placebos into the mix lol. ん is most commonly used to make "n" sounds anyway. The Japanese have no issue pronouncing "m" especially in the beginning of a word. Like in "ima" which means "now" we never confuse it for a Japanese person saying "ina" like the word "inai" which means "not in" or "not". Words that start with "en" are very clear. Like えんよ "enyo" which is another way to say "yeah."
That does happen in many languages. In Japanese the character ん is normally pronounced /ɴ/, which is a uvular nasal consonant. It is distinct from the consonants /n/ (which is an alveolar nasal) and /m/ (which is a bilabial nasal), having its point of articulation quite far from theirs. Apparently, though, its pronunciation may be realized differently in some contexts, as described in an article on Wikipedia:
Japanese phonology - Moraic nasal
Nasal assimilation. It happens pretty frequently. The "n" noise, which is the nasal, gets modified by the proceding "p" sound. The basic difference (generally) between the "m" sound and the "n" sound is mouth shape and tongue placement, and since the "p" sound has the same mouth shape as "m", the "n" sound will assimilate into an "m" sound in many languages.
The fact that えんぴつ (enpitsu) and "pencil" sound similar is just a coincidence. えんぴつ isn't a transliteration of the word "pencil"; it's actually what is called a calque, or a word-for-word translation. When you write えんぴつ in kanji, it becomes 鉛筆. 鉛 means "lead" and 筆 means "writing brush", making 鉛筆 a word-for-word translation of the English "lead pencil".
Technically both "empitsu" and "enpitsu" should be right as romanizations of the word, depending on which rules you follow. However, I haven't really seen someone transliterate it as "empitsu". For learning purposes both have their merits and demerits. "Empitsu" is closer to the pronounciation, while "enpitsu" is more like how it's written in hiragana. Then again, in my opinion, you shouldn't rely on romaji too much when learning Japanese since it's counter-productive for learning to write/read (in) kana and kanji.
Cognates are words that stem from the same root word, so they sound similar and may have the same meanings because they evolved from one word. False cognates are words that coincidentally sound similar, but actually mean different things. They are also called "false friends" since they might make you believe that they have the same meaning since they sound alike, yet can mean completely different things.
Hope thats helps!
Funnily enough though those two words actually are related! The word パンツ (pantsu) derives from the English word pants, it just comes from the British meaning and not the American one.
The word for the American meaning of pants, ズボン (zubon), also comes from the French word jupon, meaning "underskirt".
Correction. A false cognate is a word that sounds similar to another word and also has a similar meaning but is not etymologically related. For example, Japanese arigatou and Portuguese obrigado* sound similar enough and also mean the same, but they're not related to each other. They're false cognates.