Spelling the /i/ Sound: η ι υ ει οι

If there is one page in the whole Greek spelling section to study hard, it is this one. The sound /i/ — the "ee" in "see" — can be written five different ways: η, ι, υ, ει, and οι (and, in a handful of learned words, a sixth, υι). All six are pronounced exactly the same. There is no audible clue whatsoever telling you which spelling a given word takes; you cannot sound it out. This is the number-one spelling challenge for learners and for native Greeks, and it is drilled for years in Greek schools. The path through it is not memorising every word — it's learning the grammatical patterns and word families that make most of the choices for you.

Five (or six) letters, one sound

Here are all the spellings of /i/, each in a real word:

That one sentence uses three of the /i/-spellings: η (the article — twice — and again in μεγάλη and αδερφή), ι and η together in Νίκη, and ει in είναι. Read aloud, every /i/ is the same sound; on the page, three different letters.

The high-value patterns

Most of your /i/ letters sit in endings, and endings are predictable. Learn these five patterns and you'll spell the majority of /i/ sounds correctly without knowing anything about the individual word.

Pattern 1 — Feminine nouns end in -η

A very large class of feminine nouns ends in -η: νίκη, τιμή, αγάπη, τέχνη, ζωή, φωνή. For a declinable feminine noun in this class whose ending sounds /i/, η is the high-value first choice; indeclinable names and loans must be learned individually.

Note that δυνατή ("strong," feminine) also ends in -η — because adjective feminines follow the same rule (Pattern 4 below). More on why the ending signals gender on the noun gender page.

Pattern 2 — Neuter nouns (especially diminutives) end in -ι

A big family of neuter nouns ends in -ι (iota): παιδί, σπίτι, κλειδί, τραπέζι, ποτήρι, ψωμί. (Other neuters end in -ο or -ό — δώρο, νερό — but when the ending sounds like /i/, it's spelled -ι.) Above all, diminutives in -άκι always take iota: καφεδάκι, σπιτάκι, παιδάκι, κοριτσάκι.

Pattern 3 — Verb endings: -εις (2sg) and -ει (3sg) in a major conjugation

In the large Type A class, and in applicable contracted -ώ paradigms, the present-tense forms for “you” (singular) and “he/she/it” use -εις and -ει: γράφεις, γράφει; τρέχεις, τρέχει; θεωρείς, θεωρεί. Within these paradigms the spelling is fixed: the endings do not take η or ι. Other conjugations have different endings, such as αγαπάς and αγαπά(ει), so -εις/-ει is a high-value pattern rather than a rule for every Greek verb.

These are among the most frequent verb endings in the language. Once a verb belongs to one of these paradigms, -εις / -ει reliably supplies the /i/ spelling.

Pattern 4 — Adjective feminine singular ends in -η

Many common adjectives have a feminine singular in -η: καλή, μικρή, μεγάλη, όμορφη, ακριβή, φτηνή, δυνατή. Other adjective classes use -α or -ιά, as in ωραία and γλυκιά. When the feminine ending is the /i/ sound in this major class, it is spelled -η.

Notice πόλη ("town") also ends in -η — it's one of the feminine -η nouns from Pattern 1.

Pattern 5 — Learned and scientific words keep υ

Many inherited roots, including roots common in learned and scientific vocabulary, keep etymological υ: σύστημα, γύρος, μυστικό, γυμναστήριο, φύση, ύλη, σύμβολο, τύπος. Formal register alone does not predict the spelling; the useful strategy is to learn a familiar root and then reuse its υ across its word family.

And οι — the masculine -ος plural ending

The spelling οι shows up above all in the nominative plural of the large masculine -ος class and in the plural article: ο άνθρωπος → οι άνθρωποι, ο δρόμος → οι δρόμοι, ο φίλος → οι φίλοι. In this class, both the article οι and the noun ending -οι take omicron-iota. Other masculine classes have plurals such as οι άντρες or οι συγγενείς, so learn the ending with the noun's declension.

Word families keep their spelling

Beyond the endings, remember that a root normally carries its spelling into related words. Learn κλείνω with κλείσιμο, κρύο with κρυώνω, and λύνω with λύση. Recognising the family lets one stored spelling guide several words instead of making you guess from sound each time.

Homophones told apart only by their /i/-spelling

Because five letters share one sound, Greek is full of word pairs that sound identical and are distinguished purely by which /i/-letter they use. The spelling is the meaning:

Say it aloud and καλή and καλεί are the same syllables; only the page tells them apart. This is why Greek treats spelling as real content, not a formality — and why the endings (Pattern 3 explains καλεί's -εί; Pattern 4 explains καλή's -ή) are your fastest way to get homophones right.

Common Mistakes

1. Ending a feminine noun from the large -η class in -ι. In this class the ending is -η.

2. Writing a Type A verb's 3sg ending as -η. In this paradigm, the present 3rd-person singular ending is -ει.

3. Replacing a learned υ with ι. Words from the learned/scientific stock keep the etymological υ.

4. Confusing a homophone pair. κλείνω ("I close") and κλίνω ("I bend/decline") sound the same; the spelling picks the meaning.

5. Spelling the plural of a masculine -ος noun with η or ι. This class takes -οι, alongside the plural article οι.

Key Takeaways

• η, ι, υ, ει, οι (and rare υι) all sound identical: /i/. You can't hear which a word takes.
• Attack it through endings: feminine noun/adjective -η (νίκη, καλή), neuter and diminutive -ι / -άκι (παιδί, καφεδάκι), verb -εις / -ει in applicable paradigms (γράφεις, γράφει), and masculine -ος plural -οι (οι δρόμοι).
• Many inherited and learned roots keep etymological υ (σύστημα, γύρος), and word families share a root spelling (κρύο, κρυώνω; κλείνω, κλείσιμο).
• The letters carry meaning in homophones: καλή vs καλεί, κλείνω vs κλίνω, λύπη vs λείπει.
• See the spelling overview for the why, vowel digraphs for how ει and οι are read, and noun gender for why -η signals a feminine.