Nick on Quora

Roman alphabet digraphs were invented with the digraphs Latin used to represent Greek aspirated letters: <ch th ph>. So <ch> was available very very early on to languages using the Roman alphabet, to represent new sounds.

Palatal sounds are notoriously unstable phonologically: once /k/ goes to [c] (as it did in late Latin), it can then move on to any of [tɕ, tʃ, ʃ, s].

As a back consonant, <c> could be used to convey anything velar or palatal, or even palatoalveolar, given the possible targets of phonetic change for a fronted /k/.

• So <ch> could end up being conscripted as something velar—like a velar fricative /x/, in German.
• Or it can be used to mean that the velar is velar and not palatalised, like <chi> in Italian.
• Or it can be used to mean something palatal instead of velar—like the palatal stop /c/  in Old French.
• Or it can be used to represent any phoneme that the unstable /c/ ends up sounding like, including the palatoalveolar /ʃ/ in Modern French, or /tʃ/ in English and Spanish.

The claim of Natural semantic metalanguage is that you can with around 60. It was a party trick of Australian linguistics undergrads to speak in NSM; it becomes very stilted very quickly, but in principle you can define a lot of notions with a limited vocabulary, as the asker alludes to. NSM is of course a definition language, rather than a communicative language, but that seems to be what OP is after.

Basic English tries with 850 words, and xkcd’s Up Goer Five English that Robert Collins mentions seems to be of the lineage of Basic English.

The collation of Greek and Roman are pretty similar, as Philip said, once you factor out archaisms, and the tendency to insert new letters at the end of the alphabet.

The original Roman alphabet matches to the original Greek alphabet pretty well:

A Α
B Β
C Γ
D Δ
E Ε
F Ϝ
G —
—  Ζ
H Η
— Θ
I ~ J  Ι
K  Κ
L Λ
M Μ
N Ν
— Ξ
O Ο
P Π
Q Ϙ
R Ρ
S Σ
T Τ
U ~ V Υ
— Φ
— Χ
— Ψ
— Ω
X (Ξ)
Y (Υ)
Z (Ζ)

The Greek equivalents of F and Q fell out of use. J and V are variants of original I and U, and appended after them. W, when it developed, was a variant of V, and appended after it. Ζ, Θ, Ξ, Φ, Χ, Ψ, Ω were left out of the original Roman alphabet—although as it turns out, Χ in the western Greek alphabet corresponded to Ξ in the eastern, so it was in the right kind of place. X, Y, Z were imports from Greek, and stuck on the end.

The only real oddity is G and Ζ being in the same position. G was invented in the Roman alphabet as a variant of C; the theory is that it was slotted in where Greek Ζ used to be, precisely because Greek Z had dropped out after F. See G

Cyrillic patterns closely to Greek too, if you allow for variants of letters being inserted in place, and new letters being appended at the end.

See early Cyrillic alphabet:
А Α
БВ Β
Г Γ
Д Δ
Е Ε
ЖЅЗ Ζ
И Η
— Θ
І Ι
К Κ
Л Λ
М Μ
Н Ν
— Ξ
О Ο
П Π
Р Π
С Σ
Т Τ
Ѹ Υ
Ф Φ
Х Χ
— Ψ
Ѡ Ω
ЦЧШЩЪЫЬѢЮꙖѤѦѨѪѬѮѰѲѴҀ

Б was inserted as a variant of Β. Ж and Ѕ were inserted as variants of З = Ζ. Θ, Ξ, Ψ were left out as unnecessary to Slavic, though there were then re-appended at the end, to transliterate Greek:  ѮѰѲ. In fact the very last letter appended, Ҁ, was appended for Greek numerals: ϟ, koppa (which earlier looked like Ϙ).

To add to the other answers, and to answer a slightly different question 🙂 : between the 1300s and the 1800s, the region *around* Athens was substantially Albanian-speaking (Arvanitika). That’s why the map Brian Collins included in his answer has a patch of white. (A friend of mine once called that patch of white the αλβανότρυπρα, “the Albanian hole”.)

In fact, the village of Athens itself had two languages: Old Athenian, an archaic dialect of Modern Greek related to the dialect of Mani; and Arvanitika. Which is where the district of Plaka got its name from, from the Albanian pllakë, “old”: it’s the old town.

Any Jews living in Athens would have spoken Jewish Greek (Yevanic language). Romani would presumably also have been spoken—although speakers of the Agia Varvara variant of Romani, which is famous for having been studied linguistically [A Glossary of Greek Romany As Spoken in Agia Varvara (Athens)], are refugees from Turkey. The Muslims of Athens, I assume, spoke Turkish: I’m not aware of mass conversions of ethnic Greeks to Islam there, as had taken place in Crete.
 
Of course once Athens became the capital of Greece, both Old Athenian and Arvanitika were wiped out by the influx of speakers of what was to become Modern Standard Greek—a mixture of Peloponnesian and Katharevousa.

The harder bits. 🙂 In particular:

* The fine differentiations in aspect and tense, including Lexical aspect (achievement, event, accomplishment, state). Hard to speak, not sure how successfully they’ve been taken up, but fascinating.
* The abstraction particles: Events, Qualities, Quantities, And Other Vague Words: On Lojban Abstraction. Even more fascinating, even harder to speak.
* Raising (linguistics) constructions, and the eye opener of how prevalent they are in natural languages: Events, Qualities, Quantities, And Other Vague Words: On Lojban Abstraction [tu’a, jai]
* The genuinely eccentric 🙂 approach to anaphora
* Like James Wood said, the open-ended case roles/prepositions, and their kaleidoscopic version of case grammar
* The argument structures of compounds (lujvo), which was more case grammar, and which I may have had a role in advocating: seljvajvo – La Lojban
* The text structure markers, which I found neat, at least in writing 🙂 Putting It All Together: Notes on the Structure of Lojban Texts

The attitudinals and tenses, actually, not so much: they were quite attention grabbing, so I didn’t find them as appealing. 🙂

The logical connectives were most useful to me in demonstrating how little  natural language connectives have to do with truth-conditional logic. 🙂 If is seldom translated successfully as ganai.

Gave me a podium to be a language pioneer for a little while. I gather I am still revered in some circles as the first fluent speaker. 🙂

Gave me a severe sequence of intellectual challenges at a time when I needed it; helped me sharpen several of my skills, including writing in English. 🙂

Made me a linguist and not just a linguaphile. The emphasis of Lojban on formal semantics (not just formal logic) made me more acutely aware of language structure, and drove me to study it formally—even if what I ended up studying was rather fluffier (a common outcome for those who come to Linguistics from Computer Science).

The rules are here: The Shape Of Words To Come: Lojban Morphology

The summary of the rules are:
* End in a consonant
* Start in a pause or consonant
* Do not include “la”, “lai”, or “doi”, since they are particles introducing names
* Come close to Lojban phonology
* Allow stress not to be on the penult, but indicate it by capitalisation.

Because of the American basis of the Lojban community, you will see djan /dʒan/ more often than djon /dʒon/ for John.

-s is the default final consonant, though some have used other defaults, including -j or -x —because they are less common.

English being schwa-rich, you will see lots of <y> in English names. So Melissa [mɛˈlɪsə] > melisy + s > .melisys. Washington [wɑʃɪŋtən] would be
.UAcintyn.

Nick Enfield [Page on sydney.edu.au]  (who I did linguistics with, and boy does he look different twenty years on) just got an Ig Noble [Improbable Research] for claiming the universality of Huh? (The Syllable Everyone Recognizes, Is ‘Huh?’ a universal word?)

Of course the realisation of Huh? does differ by language; in the Mediterranean, for example, it is E? But the general idea is a mid vowel (as close to a schwa as your language allows), with a questioning tone.

I’ll note anecdotally that the Greek for Ouch! is ox! or ax!—but that because of cartoons, Greek kids now spontaneously say ouch! (I heard my young cousins do it twenty years ago.) Even though /tʃ/ is not even a phoneme of standard Greek. So short expletives, discomfitingly, can be borrowed between languages, just as everything else can.

There used to be a lot more Turkish words in Greek, but purism and changes in institutions have gotten rid of a lot of them. There are still a fair few in daily use. Nikos Sarantakos’ blog [Page on wordpress.com] has a list of 218 Turkish words that remain in daily use. I am taking out of the list words that are only used in fixed expressions (e.g. χρόνια και ζαμάνια “years and zaman = it’s been a very long time”), and words that I think are somewhat specialised or antiquated, and I reduce them down to the following 140:

Αγιάζι (frost),
Αλάνα (open space),
Γιακάς (collar),
Γιαπί (building site),
Γιαούρτι (yoghurt)
Γιλέκο (vest)
Γινάτι (stubbornness),
Γλέντι (party)
Γούρι (good luck),
Γρουσούζης (jinxed),
Εργένης (bachelor),
Ζόρι (difficulty),
Καβγάς (argument),
Καβούκι (shell),
Καζάνι (cauldron),
Καλούπι (mould),
Κάλπικος (fake),
Καπάκι (lid),
Καρπούζι (watermelon),
Κασμάς (pickaxe)
Κατσίκα (goat)
Κέφι (good mood)
Κιμάς (mincemeat),
Κοτζάμ (huge),
Κοτσάνι (stalk),
Κουβάς (bucket),
Κουμπαράς (piggybank),
Λεβέντης (brave),
Λεκές (stain),
Λούκι (gutter),
Μαγιά (yeast),
Μαγκάλι (brazier),
Μαϊντανός (parsley)
Μανάβης (greengrocer),
Μαράζι (withering away),
Μαραφέτι (gadget),
Μεζές (tapas),
Μενεξές (violet),
Μεντεσές (hinge),
Μεράκι (yearning),
Μουσαμάς (canvas),
Μπαγιάτικο (stale),
Μπακάλης (grocer),
Μπαλτάς (axe),
Μπάμια (okra),
Μπαμπάς (dad),
Μπαρούτι (gunpowder),
Μπατζάκι (shin),
Μπατζανάκης (brother in law),
Μπατίρισα (go broke),
Μπαχαρικό (spice),
Μπεκρής (drunkard),
Μπελάς (trouble),
Μπογιά (paint),
Μπόι (height),
Μπόλικος (plenty)
Μπόρα (downpour)
Μπουλούκι (crowd),
Μπουντρούμι (dungeon),
Μπούτι (thigh),
Μπούχτισμα (fed up),
Νάζι (coyness),
Νταντά (nanny),
Ντιβάνι (divan, sofa)
Ντιπ για ντιπ (totally),
Ντουβάρι (wall),
Ντουλάπι (cupboard),
Ντουμάνι (smoke),
Παζάρι (market),
Παντζάρι (beetroot),
Πατζούρι (window blinds),
Παπούτσι (shoe),
Περβάζι (window sill),
Πιλάφι (rice, pilaf),
Πούστης (faggot [derogatory])
Ρουσφέτι (corruption),
Σακάτης (crippled),
Σαματάς (noise),
Σεντούκι (chest, box),
Σινάφι (guild),
Σιντριβάνι (fountain),
Σιρόπι (syrup),
Σαΐνι (genius),
Σοβάς (plaster),
Σόι (family, lineage),
Σοκάκι (alley),
Σόμπα (heater),
Σουγιάς (pen-knife),
Σουλούπι (shape, form)
Ταβάνι (roof),
Ταμπλάς (stroke),
Ταπί (penniless)
Ταραμάς (taramasalata, fish roe),
Τασάκι (ashtray),
Ταψί (baking tray),
Τεμπέλης (lazy),
Τενεκές (can),
Τεφτέρι (ledger)
Τζάκι (fireplace),
Τζάμι (windowpane),
Τζάμπα (for free, gratis),
Τόπι (ball),
Τσακάλι (jackal),
Τσακμάκι (lighter),
Τσάντα (bag),
Τσαντίρι (tent),
Τσαπατσούλης (messy),
Τσάρκα (stroll),
Τσαντίζω (irritate),
Τσαχπίνης (cunning),
Τσέπη (pocket)
Τσιγκέλι (hook),
Τσιγκούνης (greedy)
Τσιμπούκι (smoking pipe),
Τσιράκι (henchman),
Τσίσα (pee)
Τσομπάνης (shepherd)
Τσουβάλι (sack),
Τσουλούφι (tuft of hair),
Φαράσι (dustpan),
Φαρσί (fluent),
Φιστίκι (peanut),
Φιτίλι (wick),
Φλιτζάνι (cup),
Φουκαράς (poor guy [term of compassion]),
Φουντούκι (hazelnut),
Φραντζόλα (loaf),
Χαβούζα (water tank),
Χάζι (pleasure),
Χαλαλίζω (forgive),
Χάλι (mess),
Χαλί (carpet),
Χαμάλης (porter)
Χάπι (pill),
Χαράμι (waste),
Χαρτζιλίκι (pocket money),
Χασάπης (butcher),
Χατίρι (favour),
Χαφιές (informant),
Χούι (quirk)

Most of these, you would be struggling to replace with a Greek word idiomatically. Please don’t make me provide the Turkish originals for all of them. [But see the admittedly somewhat messy list given as [1] in Achilleas’ answer.]

A couple of these are Rückwanderer [TIL a Rückwanderer (German for “one who wanders back”) is a word that enters another language, develops a new form or meaning there, and is re-borrowed into the original language. • /r/todayilearned], such as φουντούκι < fındık < Ποντικόν, φιστίκι < fıstık < πιστάκιον, τεφτέρι < tefter < διφθέρα.

Ergative languages are a very hard thing to wrap your head around, if you don’t speak one. A *very* crude way to explain it is: verbs look like they’re passive by default:

I am slept.
I am killed by the enemy.

If you’re just sitting there, including having something done to you, you’re the subject.  (Absolutive case)
If you do something to someone (transitive verb), you get extra grammar (the ergative case): you are *not* the subject.

In nominative-accusative languages, if you do something to someone, you’re the subject, and whoever has something done to them is the object.

The way linguists explain it is by having S for subjects of intransitive verbs, A for agents of transitive verbs, and O for objects of transitive verbs:

I (S) sleep
The enemy (A) kills me (O)

In nominative-accusative languages, S and A are in the same case (nominative). In ergative-absolutive languages, S and O are in the same case (absolutive).

English actually has an ergative feature tucked away: the –ee suffix. If the verb is intransitive, –ee goes with the subject: I retire, I am a retiree. If the verb is transitive, –ee goes with the *object*: They paroled me, I am a parolee. In ergative-absolutive terms, –ee goes with the noun that would be in the absolutive case.

European languages are nominative-accusative, but a whole lot of languages in the world are ergative-absolutive. A further complication is that some languages are split-ergative: their verbs are nominative-accusative in some tenses, and ergative-absolutive in other tenses.

I said that ergative-absolutive verbs acts as if they are in the passive, which is why “if you’re just sitting there, you’re the subject”. Nominative-accusative languages have a way to flip the subject and object of transitive verbs, and calls that the passive. You guessed it: ergative-absolutive languages have a way to  flip the subject and “object” of transitive verbs: “The enemy is is-killed-ed by me = The enemy kills me”. And that mechanism is called… an anti-passive.