The physical impossibility of turning things into people is something language does with great ease. If you’re from Rome you are a Roman, if you do political science you are a political scientist, and if you’re into Star Trek, you are a Trekie. All you need is the right suffix and everything is possible. The problem is, what is the right suffix? Here is a selection of the most common candidates.
Perhaps the best place to start is with the character 人 (jin, human). It can be attached to the name of any country or region in the world to refer to a person from that place. Which is very convenient because, unlike in English where you have to choose from a whole catalog of -ese, -ers, -ans and -ians, in Japanese there’s only -jin. No matter if you’re from Finland (フィンランド人, Finrandojin), from Kansai (関西人, Kansaijin), or from Mars (火星人, Kaseijin), jin will always work.
Other types of people that are defined by the -jin ending are bijin (美人, beauty), rinjin (隣人, neighbor) and rōjin (老人, old man), not to forget fujin (婦人, lady), shujin (主人, husband) and, if applicable, aijin (愛人, lover), among others. The type of person changes slightly when the reading of the character becomes nin. Examples are byōnin (病人, sick person), shōnin (証人, witness), honnin (本人, the person him/herself), and tanin (他人, other person). Note that 人 can also be read as hito — the native Japanese reading — as in koibito (恋人, lover) and tabibito (旅人, traveler).
A second frequently used person suffix is 者, which can read as either mono or sha, again resulting in a slightly different meaning. The former is found in terms like wakamono (若者, youth), namakemono (怠け者, sluggard), and ochōshimono (お調子者, a person who is easy prey to praise or flattery). The latter appears in a handful of names for professions, such as isha (医者, doctor) and kisha (記者, journalist), as well as in more abstract person words, for example kankeisha (関係者) and tōjisha (当事者), both of which refer to a “whom it may concern” person. In some cases (hint: short word length and n-ending) the reading may change from sha to ja, which gives us kanja (患者, patient), ninja (忍者, ninja) and shinja (信者, believer).
A larger number of professions are indicated by the suffix 家, which literally means house and is read ka. You can be a sakka (作家, writer), seijika (政治家, politician), jūdōka (柔道家, judoka) or a bōkenka (冒険家, adventurer) — though this last one is no longer a profession in the narrower sense. Two other suffixes used to define people by what they do are 士 and 師, which both read as shi. The former gives us bengoshi (弁護士, lawyer), zeirishi (税理士, tax accountant), and shōbōshi (消防士, firefighter), the latter kyōshi (教師, teacher), kangoshi (看護師, nurse) and majutsushi (魔術師, magician).
People in some form of dependent employment are often referred to by the character 員 (in, literally, “member”). This applies to both kōmuin (公務員, public servants) and kaishain (会社員, company employees), just as it holds for the kyōin (教員, teaching staff) and shokuin (職員, office staff) of a school. For more independent types of work, usually involving some sort of craft, the character 屋 (ya) is used, often in combination with the honorific suffix –san (さん). These names refer to both the shops on your local shopping street and the professionals who work inside them, including yaoyasan (八百屋さん, greengrocer), tōfuyasan (豆腐屋さん, tofu shop owner) and kurīninguyasan (クリーニング屋さん, dry cleaner), to name but a few. Here too, there are a few candidates that do not relate to any profession, or at least not one subject to income tax: a ganbariyasan (頑張り屋さん, someone who always gives their best), for instance, or a nonbiriyasan (のんびり屋さん, someone who takes things easy).
Even in the domain of person suffixes, Japanese occasionally can’t resist borrowing from English. The best-known example is man (マン), as in the made-in-Japan loanword sararīman (サラリーマン, office worker). Combinations with words that are not written in katakana are also possible, as in ginkōman (銀行マン, banker) and eigyōman (営業マン, sales representative). Another loanword suffix is rian (リアン), derived from the English -ian. It denotes members of a certain group with some eccentric mindset, as for instance obatarian (オバタリアン, slightly annoying middle-aged women), sonatarian (ソナタリアン, same as previous with a foible for Korean TV dramas), and sutabarian (スタバリアン, “Starbuckers”).
Finally, there’s rā, which is a somewhat unfaithful copy of the English -er. It occurs in a handful of terms only, including mayorā (マヨラー, a person who is crazy about mayonnaise) and nichannerā (2チャンネラー, a regular commenter on the online 2channel bulletin board).
What you do is what you are, says Ancient Chinese philosopher Laozi. And even though he wasn’t referring to greengrocers or dry cleaners — let alone Internet addicts and mayonnaise lovers — he certainly had a point.