Avokado olgunlaşınca yumuşuyor.

Olgunlaşınca means when it ripens, once it ripens, or when it gets ripe.

It comes from:

• olgun = ripe, mature
• olgunlaşmak = to ripen, to become ripe
• olgunlaşınca = when/once it ripens

So the structure is basically:

• olgunlaş- = ripen / become ripe
• -ınca = when, once

Turkish often makes this kind of when X happens clause by attaching -ınca / -ince / -unca / -ünce directly to the verb.

Here, -ınca creates a time clause meaning when, once, or sometimes after in the sense of after it has happened.

So:

• gelince = when he/she/it comes
• bitince = when it finishes
• olgunlaşınca = when it ripens

In this sentence, Avokado olgunlaşınca yumuşuyor, the first part sets the condition in time:

• When the avocado ripens, ...
• ... it softens / gets soft.

It is not a separate word like English when; it is attached to the verb.

-laş- often means become or turn into when added to a noun or adjective.

So:

• olgun = ripe
• olgunlaşmak = to become ripe, to ripen

This is a very useful pattern in Turkish. For example:

• güzel = beautiful

• güzelleşmek = to become beautiful

• sert = hard
• sertleşmek = to become hard

So olgunlaşmak is not just to be ripe; it is to become ripe.

Yumuşuyor comes from yumuşamak, which means to become soft or to soften in the intransitive sense.

So yumuşuyor means:

• it is becoming soft
• it gets soft
• it softens

In this sentence, it describes what happens to the avocado as it ripens.

A useful contrast:

• yumuşamak = to become soft
• yumuşatmak = to soften something

So the sentence is about the avocado itself changing, not about someone softening it.

This happens because of a common sound change with the -yor form.

The verb is:

• yumuşamak

Its stem is:

• yumuşa-

When -yor is added to verbs ending in -a or -e, that final vowel changes to a narrower vowel. So:

• başla- → başlıyor
• anla- → anlıyor
• yumuşa- → yumuşuyor

So yumuşuyor is the correct form.

This is something you will see often with Turkish verbs in the -yor form.

Formally, yumuşuyor is the -yor form, often called the present continuous.

But in Turkish, this form is used more widely than English is ...-ing. It can express:

• something happening right now
• something that regularly happens
• something generally true in a certain situation

So here, yumuşuyor does not have to mean the avocado is literally softening at this exact second. It can also mean:

• When an avocado ripens, it softens
• Avocados get soft when they ripen

That broader use is very normal in Turkish.

It means it is becoming soft or it gets soft, not simply it is soft.

That difference matters:

• yumuşak = soft
• yumuşamak = to become soft

So:

• Avokado yumuşak. = The avocado is soft.
• Avokado yumuşuyor. = The avocado is getting soft / softening.

In your sentence, the focus is on the change of state.

Turkish often leaves out subject pronouns when they are understood from context.

Here, the subject is already clear from avokado, so Turkish does not need a separate word for it.

English usually says:

• When the avocado ripens, it softens.

Turkish can simply say:

• Avokado olgunlaşınca yumuşuyor.

The noun avokado is enough to establish the subject.

It can easily have a general meaning, even though the noun is singular.

Turkish often uses a singular noun for general truths or typical behavior. So avokado here can mean:

• an avocado
• the avocado
• avocados in general

depending on context.

So this sentence can naturally be understood as a general fact:

• Avocados soften when they ripen.

Turkish does not always pluralize nouns in the same places English does.

Turkish does not have articles that work like English a/an and the.

So avokado by itself can mean:

• an avocado
• the avocado
• sometimes even avocados in a general sense

The exact meaning depends on context.

That is why the sentence can sound natural without any extra word before avokado.

Yes. Avokado olgunlaşınca yumuşar is also correct.

The difference is mainly one of style and nuance:

• yumuşuyor sounds more conversational and vivid
• yumuşar sounds a bit more like a general rule, fact, or textbook statement

So:

• Avokado olgunlaşınca yumuşuyor.
• Avokado olgunlaşınca yumuşar.

Both can mean When an avocado ripens, it softens.

The given order is very natural:

• Avokado olgunlaşınca yumuşuyor.

It follows a common Turkish pattern:

• topic/subject + when-clause + main verb

Turkish word order is fairly flexible, but changing it changes emphasis. For example, you could also hear:

• Olgunlaşınca avokado yumuşuyor.

That is possible, but the original version sounds more neutral and straightforward.

So the sentence order is not completely fixed, but the version you have is a very normal one.