Περίμενε δύο λεπτά στον διάδρομο, παρακαλώ.

Περίμενε is the imperative (a command) meaning Wait! It comes from the verb περιμένω (I wait). In this sentence it’s 2nd person singular, so it’s addressed to one person in an informal/neutral way.

Yes. Περίμενε can also be the past form (imperfect) meaning he/she was waiting. In writing, context and punctuation usually make it clear: here the comma and παρακαλώ strongly suggest it’s an instruction: Wait… please.

Use the plural/formal imperative:

• Περιμένετε δύο λεπτά στον διάδρομο, παρακαλώ. (Wait two minutes in the corridor, please.)

Both are common. δύο is the standard spelling; δυο is a very frequent simplified spelling, especially in informal writing. They’re pronounced the same.

Because it’s two minutes, Greek uses the plural λεπτά (minutes). For one minute:

• ένα λεπτό (one minute)

στον is a contraction of σε + τον:

• σε = in/to/at
• τον = the (masculine accusative singular)

So στον means in the / to the (masculine).

Because the preposition σε requires the accusative case. The dictionary form is ο διάδρομος (the corridor, nominative), but after σε/στον it becomes accusative: (στον) διάδρομο.

It depends on the gender of the noun:

• Masculine: στον (e.g., στον διάδρομο)
• Feminine: στη(ν) (e.g., στην αίθουσα)
• Neuter: στο (e.g., στο γραφείο)

παρακαλώ works like please, softening the command. It can appear at the end (as here) or earlier:

• Παρακαλώ, περίμενε δύο λεπτά στον διάδρομο. You may also hear σε παρακαλώ (more personal/insistent: please, I’m asking you).

Greek word order is fairly flexible. You can reorder for emphasis without changing the basic meaning, for example:

• Περίμενε στον διάδρομο δύο λεπτά, παρακαλώ. (emphasis on where to wait)

A rough guide:

• Περίμενε: pe-REE-me-ne
• δύο: THEE-o (the δ is like the th in this)
• λεπτά: lep-TA
• στον: ston
• διάδρομο: THYA-thro-mo (stress on Διά-)