Κάθε εβδομάδα μιλάω με τη γιαγιά μου στο τηλέφωνο.

Yes. Κάθε εβδομάδα means every week.

• κάθε = every / each
• εβδομάδα = week

A useful point is that Greek often uses κάθε + singular noun for expressions like:

• κάθε μέρα = every day
• κάθε μήνα = every month
• κάθε χρόνο = every year

So even though English also uses the singular in every week, learners sometimes expect a plural idea because the meaning is repeated time.

Because after κάθε, Greek normally uses the singular:

• κάθε εβδομάδα = every week
• not κάθε εβδομάδες

This is just like English every week, not every weeks.

Because Greek often leaves out subject pronouns when the verb already shows who is doing the action.

Here, μιλάω means I speak / I talk, so εγώ is not necessary.

• μιλάω = I talk
• εγώ μιλάω = I talk / I talk

You can add εγώ for emphasis, but in a normal sentence it is usually omitted.

Yes. μιλάω is the present tense, first person singular:

• μιλάω = I talk / I am talking

In this sentence, because of κάθε εβδομάδα, it has a habitual meaning:

• Κάθε εβδομάδα μιλάω... = Every week I talk...

You may also see μιλώ, which is another accepted form. In everyday Greek, μιλάω is very common.

Yes, με usually means with, and that is exactly what happens here.

Greek often says μιλάω με κάποιον, literally I talk with someone, where English may say either:

• I talk with my grandmother
• I talk to my grandmother

So in this sentence:

• μιλάω με τη γιαγιά μου = I talk with / to my grandmother

Both are natural translations in English.

Because after the preposition με, Greek uses the accusative case.

So:

• η γιαγιά = the grandmother (nominative, dictionary-style subject form)
• τη γιαγιά = the grandmother (accusative, used after με here)

That is why the sentence has:

• με τη γιαγιά μου = with my grandmother

Both exist. Την is the full form, and τη is a very common shortened form used before many consonants in everyday Modern Greek.

So these are both possible:

• με την γιαγιά μου
• με τη γιαγιά μου

In normal speech and writing, τη γιαγιά is extremely common and natural.

In Greek, possessive words like μου often come after the noun.

So:

• η γιαγιά μου = my grandmother
• literally: the grandmother my

This is completely normal in Greek. The same pattern appears in:

• το σπίτι μου = my house
• ο φίλος μου = my friend
• η μητέρα μου = my mother

Γιαγιά means grandmother or grandma.

Depending on context, it can sound:

• neutral: grandmother
• warm/familiar: grandma

So τη γιαγιά μου can be translated as either:

• my grandmother
• my grandma

Literally, στο τηλέφωνο means on the telephone / on the phone.

It is made from:

• σε = in / at / on / to
• το = the

These combine into:

• στο = in the / at the / on the / to the

So:

• στο τηλέφωνο = on the phone

In this sentence it tells you how the conversation happens.

Because Greek commonly combines the preposition σε with the definite article.

• σε + το = στο
• σε + τη(ν) = στη(ν)
• σε + τον = στον

So στο τηλέφωνο is the contracted form of σε το τηλέφωνο, but the contracted form is the normal one to use.

It means I speak on the phone.

Even though στο can sometimes mean to the, here the full phrase στο τηλέφωνο is an expression meaning on the phone / by phone.

So:

• μιλάω με τη γιαγιά μου στο τηλέφωνο = I talk to my grandmother on the phone

It does not mean that you are speaking to the phone itself.

Yes, Greek word order is more flexible than English word order.

The original sentence:

• Κάθε εβδομάδα μιλάω με τη γιαγιά μου στο τηλέφωνο.

is a very natural neutral order.

But other orders are also possible, for example:

• Μιλάω με τη γιαγιά μου στο τηλέφωνο κάθε εβδομάδα.
• Με τη γιαγιά μου μιλάω στο τηλέφωνο κάθε εβδομάδα.

The meaning stays basically the same, but the emphasis can change. Greek often moves words around more freely than English.

A simple pronunciation guide is:

KÁ-the e-vdo-MÁ-da mi-LÁ-o me ti ya-YÁ mu sto ti-LÉ-fo-no

A few helpful sound notes:

• θ in κάθε sounds like th in think
• για in γιαγιά sounds roughly like ya
• γι before a vowel often gives a y-like sound
• λάω in μιλάω is pronounced clearly, roughly LA-o

The stress marks are important in Greek, so notice the stressed syllables:

• Κάθε
• εβδομάδα
• μιλάω
• γιαγιά
• τηλέφωνο

Yes.

• Κάθε εβδομάδα μιλάω με τη γιαγιά μου στο τηλέφωνο.
• Κάθε εβδομάδα μιλώ με τη γιαγιά μου στο τηλέφωνο.

Both are correct. Μιλάω is very common in everyday speech. Μιλώ is also correct and may sound a bit more formal or concise, depending on context and speaker.