Strictly grammatically, την becomes τη when it is not followed by κ,π,τ,ψ,ξ,γκ,μπ,ντ,τζ,τς or a vowel. So it's τη σοκολάτα. But colloquially, you can use την with every letter that follows, but not τη. So (colloquially) you can say την σοκολάτα, but never τη πέτρα. But strictly grammatically the rule above must apply.
Thank you! İs there an aid to remember these letters "κ,π,τ,ψ,ξ,γκ,μπ,ντ,τζ,τς"?
Yes! They are the consonants of "κάποτε ψάξε"=search someday, plus all double consonants.
From the κάποτε I made the KEPT-rule:
-ν is KEPT before a VOWEL or a
Κ: κ, γκ, ξ
Ρ: π, μπ, ψ
Τ: τ, ντ, τς, τζ
Ha ha - I have just spent twenty minutes finding out that κπτψ and ξ are the consonants in the words κάποτε ψάξε.
I would never have been much help in the decoding of the enigma machine in WW2. :-)
Now, is this something to do with voiced and unvoiced consonants?
Yes. Voiceless are the consonants of "Κάποτε θα σε έχω φάει" (κ,π,τ,θ,σ,χ,φ)= I will have eaten you someday. All the others (except ξ,ψ that are double consonants) are voiced.
Sorry but, I'm still confused about the articles. Could it be "Εγώ τρώω η σοκολάτα" ?
Articles change depending on what case of the noun is used. For the direct object, accusative is used. The accusative of the feminine noun is "την". So it's: nominative: η σοκολάτα, genitive: της σοκολάτας, accusative: την σοκολάτα, vocative: (-) σοκολάτα.
I think "την" is correct because in this case it is used the accusative voice, so the object of the phrase is modified along with its article.
A few days ago I met someone who lives in Greece and he told me that nobody uses the verb τρώω there, but another one which I didn't keep in my mind
The verb to eat is τρώω, there is no other verb with that meaning. It is very irregular and takes forms that are not easily associated with it if you don't speak the language, like έφαγα, but it's the only verb that means to eat. Other associated meanings, like consume, wolf down, gobble have their own equivalents. So, if you get a chance to find out, please let us know what that 'other verb' the person you met mentioned, because this does not really make any sense.
Is the morphological rule about the ν from Triandaphyllidis's Grammar? (την becomes τη when it is not followed by κ,π,τ,ψ,ξ,γκ,μπ,ντ,τζ,τς or a vowel.) My understanding is that the ν is present in more formal Gk no matter what letter follows. I'll try to memorize the rule. Thanks for the mnemonic phrase.