Most of this post has been drawn directly or indirectly from Guy Deutscher's "The Unfolding of Language", which is absolutely terrific and highly recommended.
For those of you familiar with Semitic languages, what I'm talking about will come as no surprise at all.
For those of you who aren't, but who are generally culturally literate, you will likely have encoutered the word "shalom", which is Hebrew for "peace", used as a greeting and in other social interactions as well as its literal meaning. You might greet the ambassador from Israel with "Shalom" even as you prepare to discuss ways to advance the cause of "shalom" in the Near East.
Now, English is an isolating language (although not to the extent that the Chinese language/dialects are), which means that, to some extent, English words aren't modified for grammatical purposes. "Red" is "red", whether it's applied to a fire engine or an embarrassed face or a setting sun. "Very" is "very". English isn't perfectly isolating. Nouns have two forms (in the spoken language), with the presence or absence of a plural/possessive suffix, viz. "noun" and "nouns". Verbs have a handful of forms: plain, third person singular, past (i.e. preterit), past participle, present participle/gerund. But on the whole, English just doesn't have a lot of grammatical word modifications. (I am distinguishing lexical modification, like using -al to make an adjective out of a noun, from grammatical modification.)
English is thus deeply contrasted with Romance languages, in which adjectives must agree with the gender of the noun they modify and verbs are extensively modified for number, person, and tense or mood. In French, for example, you find, just in the first person singular:
Then there's the subjunctive, the literary-only preterit (passé simple), and a host of compound tenses (e.g. j'ai mangé: I ate), all of which have different forms depending on whether the subject is I or you or she, and singular or plural.
(In spoken French, many of these forms, particularly the singular and third person plural, collapse into homophony; but the relics of difference are preserved in the written language.)
English is also contrasted with languages like German or Sanskrit, which mark nouns for their role in the sentence in what's known as a case system. Instead of using prepositions like "to" or "of" or "by" to express relationships, nouns take different forms to express the same relationships, or to indicate that the noun is acting as the subject or as the object.
I won't get into polysynthetic languages like Mohawk or Quechua except to assure you they make Sanskrit's grammatical word changes look trivial.
All this is to assure you that a great many languages the world over have a great many ways of changing a word to indicate its grammatical role in the sentence.
So it won't surprise you at all to learn that "shalom" is no different. Just as a French verb consists of a verb stem plus a grammatical ending, "shalom" has two parts, one a word stem and the rest a grammatical element.
But what the two parts are, that's where it gets interesting. The word stem is the consonants and the grammatical element is the vowels. There are no prefixes, suffixes, infixes, affixes or anything like that we'd recognize from other languages. "Shalom" consists of the word stem "slm", meaning something like "(having) peace" and a grammatical element "_a_o_", meaning something like "-ness".
Hebrew is a Semitic language, and it is entirely typical in this respect. In Semitic languages, word stems are consonant triples. They can't be pronounced; don't try saying "slm". They're abstract listings: These three consonants in this order, with this core meaning.
They become words only when they have a template applied to them. That's the grammatical element like "_a_o_". The underscores are crucial--they tell you where to put the consonants from the word stem.
The present tense in Modern Standard Arabic is a good example. The first person singular template is "a__u_u"; the second person singular masculine template is "ta__u_u". For an arbitrary stem "sng", the first person singular present tense is "asnugu"; the second person singular masculine present tense is "tasnugu".
Note that both of these templates have adjacent underscores; that means that when you stick the stem in the template, two of the stem consonants are adjacent to each other. Also note that the templates aren't restricted to just vowels; you can put consonants and even whole syllables in them. This means that the stem can be hidden pretty deeply in a word if the template is fairly complicated. If you're not used to looking for stems, two words with different templates may not look related at all, but if you're a Semitic speaker, they're immediately and profoundly related.
Templates aren't just limited to verb forms specifying tense and mode and number and so on; they can be used to create nouns, adjectives, and so on. Just as you can add "-er" to a verb in English to make a noun indicating "one who does X", you can apply a template to a stem in a Semitic language to do the same thing.
You should immediately be able to see the extraordinary power of this stem plus template combination. All you have to do is define a new template and it's immediately productive for every word stem in the lexicon. All you have to do is define a new word stem and it's immediately productive with every template in the lexicon. The combinatorics are immense.
Semitic languages have hundreds of templates from the mundane first person singular present tense to monstrosities like "one who causes to come into being the state of being in X". Drop "slm" into that template and you've got the Semitic equivalent of "peacemaker".
Hebrew and Arabic being closely related, it will not surprise you to learn that their stems for "peace" are closely related. In Hebrew, it is, more or less "shlm" (where "sh" is a single consonant, as it is in English, albeit one that has to be written with two characters in the Roman alphabet). In Arabic, as it was in proto-Semitic, it's "slm". Hebrew underwent a sound change, as languages do, but it is the same root. Similarly, the template that produced "shalom" is slightly different in Arabic, but you will not be surprised at all, and are probably already aware, that "salaam" is the same stem plus template combination as "shalom". That is, the "thingyness" template in Arabic is "_a_aa_" (where "aa" indicates a double-length "a" sound); Hebrew converted the double-a to an o.
This brings me around to the final part of my discussion, which is to talk about two specific templates in Standard Arabic. One of them means "the state of being X", and the other means "one who is in the state of being X". The former is "i__a_" and the latter is "mu__i_".
That's right. The state of being at peace is "Islam", and one who is in a state of peace is a "muslim".
Like "Christianity" and "Christian", "Islam" and "muslim" have a deep fundamental relationship, being derived from the same root by utterly standard language processes. That relationship is somewhat obscured because of the way Semitic languages work, but it's there if you know how to look.
"slm", y'all. GPM out.