Learn Hardcore Turkish: Herkes hazırmışken toplantıya başlayabiliriz. - We can start the meeting while everyone is present.

The suffix -ken attaches to verbs or adjectives to mean “while,” “when,” or “just as.” In hazırmışken, it shows that once the state of being ready is true, another action can take place concurrently or immediately after.

Why does hazırmışken include -mış, and what does it add?

The -mış in hazırmışken is the evidential/inferential past marker. It implies that the speaker is inferring or has just noticed that everyone is ready (rather than stating it from direct experience). So hazırmışken carries the nuance “now that (I see) everyone is ready” or “since everyone apparently is ready.”

How does hazırmışken differ from hazırken?

hazırken simply means “while (someone) is ready.”
hazırmışken adds the sense of inference or new information (-mış) plus -ken, turning it into “now that (I gather)…” or “since (it seems)…”
In short:

hazırken = while/when ready
hazırmışken = since/now that apparently ready

What does başlayabiliriz mean, and how is it constructed?

başlayabiliriz means “we can start.” It breaks down as follows:
• başla- = root “to start”
• -abil- = potential suffix “be able to”
• -ir = aorist/present tense marker
• -iz = 1st person plural ending
Together they form “we are able to start” → we can start.

Why use the potential mood (-abil) here instead of the simple present başlarız?

Using the potential mood (başlayabiliriz) expresses possibility or permission (“we can start”) rather than a flat statement of fact (“we start”). It’s more polite and implies “it’s OK for us to begin now.”

Can you rephrase this sentence using hazır olduğunda instead?

Yes. You could say:
Herkes hazır olduğunda toplantıya başlayabiliriz.
This means “When everyone is ready, we can start the meeting.”
The difference:

hazır olduğunda = neutral “when everyone is ready”
hazırmışken = “now that (I see) everyone apparently is ready,” adding an inferential/polite nuance.