The hardest spelling decisions in Romanian are not exotic — they are a handful of everyday pairs that sound identical but split apart in writing. Sau and s-au are pronounced the same; one means "or," the other means "they [did something]." Mai and m-ai sound the same; one means "more/still," the other means "you [did something] to me." These traps catch native speakers constantly — they are the single most common literacy error in Romanian schools and on the internet — because the ear gives you no help and the difference comes down to one hyphen, one space, or one merged-vs-separate decision. The good news: almost every pair has a reliable expansion test. If you can mentally unpack the form into its pieces (a verb cluster), it takes the hyphen; if it's a single word or a fixed adverb, it doesn't. This page walks through the worst offenders with the test for each.
sau vs s-au
Sau (one word, no hyphen) is the conjunction "or." S-au (hyphenated) is the reflexive/passive clitic se fused with the auxiliary au — "they have [done something to themselves / been done]." Test: can you finish it with a past participle? If "...what?" wants a verb (s-au întâlnit "they met"), it's s-au. If you can replace it with "or," it's sau.
Vrei cafea sau ceai?
Do you want coffee or tea? (sau = 'or', no hyphen)
S-au întâlnit din întâmplare în aeroport.
They ran into each other by chance at the airport. (s-au = se + au, a verb cluster)
sa vs s-a
Sa (one word) is the feminine possessive "his/her" (mașina sa "his car"). S-a (hyphenated) is reflexive se + the auxiliary a — "[he/she/it] has [done something]." Test: sa attaches to a noun and answers "whose?"; s-a is followed by a participle and answers "did what?"
Și-a luat mașina sa și a plecat.
He took his (own) car and left. (sa = 'his', a possessive on mașina)
S-a hotărât să se mute la țară.
He decided to move to the countryside. (s-a = se + a + hotărât, a verb)
mai vs m-ai
Mai (one word) is the adverb "more / still / again" (and also the month "May"). M-ai (hyphenated) is the clitic mă (me) + the auxiliary ai (you have) — "you have [done something] to me." Test: m-ai is always followed by a participle (m-ai sunat "you called me"); mai sits before an adjective or verb to add "more/still."
Mai vrei niște supă?
Do you want some more soup? (mai = 'more')
M-ai speriat de moarte!
You scared me to death! (m-ai = mă + ai + speriat)
ia vs i-a
Ia (one word) is the imperative "take!" of a lua, or the verb form "(he/she) takes." I-a (hyphenated) is the dative clitic îi (to him/her) + auxiliary a — "he/she has [done something] to him/her." Test: i-a is followed by a participle and means "[he] has...to him"; ia is the bare imperative or present "take(s)."
Ia loc, te rog, mâncarea e gata.
Have a seat, please, the food's ready. (ia = imperative 'take/have')
I-a dat cartea înapoi fără un cuvânt.
She gave him the book back without a word. (i-a = îi + a + dat)
neam vs ne-am
Neam (one word) is a noun, "kin / relatives / nation." Ne-am (hyphenated) is the reflexive clitic ne (us/ourselves) + auxiliary am — "we have [done something]." Test: neam is a noun you could put an article on (neamul "the family"); ne-am is followed by a participle.
Tot neamul se adună de Crăciun.
The whole family gathers at Christmas. (neam = 'kin', a noun)
Ne-am cunoscut acum zece ani.
We met ten years ago. (ne-am = ne + am + cunoscut)
numai vs nu mai
Numai (one word) is the adverb "only" (= doar). Nu mai (two words) is the negator nu + the adverb mai, meaning "no longer / not anymore." Test: if you can swap in doar ("only"), write numai; if it means "no longer," write nu mai as two words.
Numai tu mă poți ajuta acum.
Only you can help me now. (numai = 'only', = doar)
Nu mai locuiește aici de mult.
He doesn't live here anymore. (nu mai = 'no longer', two words)
odată vs o dată
Odată (one word) is the adverb "once / at one time / suddenly" (A fost odată... "Once upon a time..."). O dată (two words) is the numeral o (one) + dată (time, occasion) = "one time," and also "a date" (calendar). Test: if it means "on one occasion / formerly," it's odată; if you're counting times ("one time, not two"), it's o dată.
A fost odată un împărat...
Once upon a time there was an emperor... (odată = 'once', the storytelling adverb)
Am fost la doctor o dată anul ăsta.
I went to the doctor one time this year. (o dată = 'one time', counting occasions)
niciun vs nici un
The standard modern norm (since 2005) writes the negative determiner solid: niciun (masc.) / nicio (fem.) = "no / not a single." The older two-word nici un / nici o is now nonstandard for this meaning. (Two separate words nici... un only survive when nici is the conjunction "nor": nici unul, nici altul "neither one nor the other.") Test: if it means "not a single (noun)," write it solid; the two-word form is dated for this sense.
N-am niciun motiv să mă supăr.
I have no reason to be upset. (niciun — solid, the modern standard)
Nicio problemă, ne vedem mâine.
No problem, see you tomorrow. (nicio — solid feminine)
decât vs de cât
Decât (one word) means "than" (after a comparative) or "only" (after a negative: nu... decât "only"). De cât (two words) is the preposition de + the interrogative/quantity cât = "of how much / since how long," used in questions and amount phrases. Test: comparison or "only" → decât; a literal "of how much / how long" question → de cât.
E mai înalt decât fratele lui.
He's taller than his brother. (decât = 'than')
De cât timp aștepți aici?
How long have you been waiting here? (de cât = 'of how much [time]')
întruna vs într-una
Întruna (one word) is the adverb "continuously / nonstop" (plouă întruna "it rains nonstop"). Într-una (hyphenated) is the preposition într- + the feminine pronoun una = "in one (of them)." Test: "nonstop, all the time" → întruna; "in one [of the things]" → într-una.
Vorbește întruna, nu mai tace deloc.
He talks nonstop, he never stops. (întruna = 'continuously')
Într-una dintre camere era frig.
In one of the rooms it was cold. (într-una = 'in one', preposition + pronoun)
Common Mistakes
Writing sa (possessive) where the verb cluster s-a is needed:
❌ Sa trezit devreme azi.
Incorrect — this is the verb cluster se + a: S-a trezit devreme azi.
✅ S-a trezit devreme azi.
He woke up early today.
Writing the adverb mai where m-ai (me + you have) is meant:
❌ Mai sunat ieri?
Incorrect — 'you called me' is mă + ai: M-ai sunat ieri?
✅ M-ai sunat ieri?
Did you call me yesterday?
Collapsing "no longer" into numai ("only") — a meaning-flipping error:
❌ Numai vine pe la noi.
Incorrect — this says 'only he comes'; for 'no longer comes' use two words: Nu mai vine pe la noi.
✅ Nu mai vine pe la noi.
He doesn't come around anymore.
Using the dated two-word nici un for "not a single":
❌ Nu am nici un ban la mine.
Incorrect — the modern norm is solid: Nu am niciun ban la mine.
✅ Nu am niciun ban la mine.
I don't have a single coin on me.
Splitting decât ("than") into de cât:
❌ E mai bun de cât credeam.
Incorrect — comparative 'than' is one word: E mai bun decât credeam.
✅ E mai bun decât credeam.
It's better than I thought.
Key Takeaways
- The hyphenated member of each pair is a fused verb cluster: s-au, s-a, m-ai, i-a, ne-am — expandable into clitic + auxiliary + participle.
- The solid member is a single content word: sau (or), sa (his/her), mai (more), ia (take), neam (kin), numai (only), odată (once), întruna (nonstop).
- The two-word member counts or questions: nu mai (no longer), o dată (one time), de cât (of how much).
- The modern norm writes the negative determiner solid: niciun, nicio.
- When unsure, run the expansion test — only a genuine verb cluster earns the hyphen.
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- Hyphenation of Clitics and ContractionsB1 — Romanian uses the HYPHEN — not the apostrophe — to bolt little words onto their neighbours when they fuse into one spoken syllable: n-am, nu-i, mi-e, s-a, ne-am, te-am, l-am, într-o, dintr-un, dă-mi, du-te, spune-i, uită-te. This page sorts out when you write a hyphen, when a space, and when a solid word, and flags the high-stakes errors (neam for ne-am, sa for s-a) where the hyphen is the only thing separating two different words.
- Clitic Elision and Hyphenation SpellingB2 — The orthography of clitic contractions: when a clitic fuses across a vowel it takes a HYPHEN (m-am dus, te-ai trezit, s-a întâmplat, ți-l dau, n-am, văzându-l), but when it keeps its own syllable it is written separately (mi le dă, i se pare). The hyphen marks phonological fusion — getting it right is a hallmark of literacy.
- Punctuation ConventionsA2 — Romanian punctuation looks familiar to an English eye but the rules underneath are different: a comma DOES precede dar, iar, ci, însă but does NOT separate subject from verb or sit before most că-clauses; quotation marks are the low-opening, high-closing „…”; dialogue runs on an em-dash; and numbers use a decimal comma. This page maps the differences so your written Romanian reads as native, not as English with Romanian words.
- Why Diacritics Matter in RomanianA1 — Romanian diacritics are obligatory, not decorative. Dropping them doesn't just look careless — it changes words: peste (over) vs pește (fish), fata (the girl) vs față (face), tata (dad) vs tată (father), mana (manna) vs mână (hand). Diacritic-free Romanian is ambiguous, decodable only from context, and acceptable in casual texting but never in writing that matters.
- Spelling of LoanwordsB2 — Romanian sits between two strategies for foreign words: older loans were fully respelled into Romanian phonetics (fotbal, meci, șofer, tramvai, birou), while recent English loans are kept in their original spelling (weekend, site, mouse, manager, marketing). The seam shows in how articles and plurals attach — unadapted loans take them with a HYPHEN (site-ul, link-uri, mailuri) — and in the letters k, q, w, y, which live almost entirely in this borrowed vocabulary.