Learn Hardcore Turkish: Arkadaşım, fikirlerini özgürce söyleyebildiği için memnun. - My friend is glad that she can express her ideas freely.

The personal pronoun ben (I) is not needed here. You could say benim arkadaşım, but arkadaşım by itself is perfectly normal and already means my friend.

What exactly is going on in fikirlerini? Why all those endings?

fikirlerini is made of several parts:

fikir = idea, opinion
fikirler = opinions (plural -ler)
fikirleri = his/her opinions (3rd person possessive -i)
fikirlerini = his/her opinions as a definite object (accusative -(y)i), with a buffer -n-:
- fikirleri + (n) + i → fikirlerini

So fikirlerini roughly means “his/her opinions (as the thing being said)”.

In this sentence it’s the object of söyleyebildiği (can say). Because we are talking about specific opinions (his/her own), Turkish uses the accusative case.

Why do we use özgürce instead of just özgür?

özgür is an adjective: free.
özgürce is an adverb: freely.

The suffix -ce/-ca can turn many adjectives/nouns into adverbs:

yavaş → yavaşça (slow → slowly)
dikkatli → dikkatlice (careful → carefully)

Here, it’s describing how he/she says the opinions:

özgürce söylemek = to say (something) freely

If you said fikirlerini özgür söylemek, it would sound wrong, because adjectives don’t directly modify verbs in Turkish; you need the adverbial form özgürce.

What does the -ebil- part in söyleyebildiği mean?

-ebil- / -abil- is an ability/possibility marker and corresponds roughly to “can” or “be able to” in English.

söylemek = to say / to tell
söyleyebilmek = to be able to say

So inside söyleyebildiği, we still have that meaning of “can say”:

söyleyebil- = can say
plus the rest (-diği) which turns it into a noun-like clause (see next question).

How is söyleyebildiği formed, and what does the ending -diği do?

söyleyebildiği is built from the verb söyleyebilmek (“to be able to say”):

Start with the verb stem: söyleyebil-
Add the -dik/-dık/-duk/-dük nominalizing/relative suffix, here as -diğ- (because of vowel harmony and consonant change)
Add the 3rd person possessive ending -i (his/her/its)

So:

söyleyebil- + diğ + i → söyleyebildiği

Function:

-dik/-diği turns a verb into a noun-like clause:
- geldiği = the fact that he/she came / where he/she comes
- yazdığı = what he/she writes / that he/she writes

In our sentence, söyleyebildiği means roughly “the fact that he/she can say (them)” or “(his/her) being able to say (them)”. This whole chunk then combines with için to give “because” (see below).

Why does söyleyebildiği have a 3rd person possessive ending -i? Who is possessing what?

In Turkish nominalized clauses (with -dik/-diği, -mek/-me, etc.), the subject of the clause is marked by a possessive suffix on the verb form.

Here the implied subject is arkadaşım (my friend), but it isn’t repeated:

(Arkadaşım) fikirlerini özgürce söyleyebildiği için… → literally: "because his/her being able to say his/her opinions freely …"

The -i on söyleyebildiği means “his/her”, and it tells us that he/she (my friend) is the one who can say the opinions.

If we wanted a different subject, we’d mark it with genitive + an appropriate possessive ending:

Benim fikirlerimi özgürce söyleyebildiğim için…
Senin fikirlerini özgürce söyleyebildiğin için…
Onun fikirlerini özgürce söyleyebildiği için…

How does …söyleyebildiği için… mean “because he/she can say (them)”? Why use için?

The structure is:

[verb + -diği] + için = because (subject) [verb]

So:

söyleyebildiği için ≈ “because (he/she) can say (them)”

More literally:

söyleyebildiği = his/her being able to say (them)
için = for / because of

So the whole phrase is “because of his/her being able to say his/her opinions freely.”

Compare:

Yağmur yağdığı için dışarı çıkmıyoruz.
= We aren’t going out because it is raining.

In spoken Turkish, you can also use çünkü with a full finite clause:

Arkadaşım memnun, çünkü fikirlerini özgürce söyleyebiliyor.
= My friend is happy, because he/she can say his/her opinions freely.

Both are correct; the sentence you’re studying uses the “…diği için” pattern.

Why isn’t there a separate word for “he/she” in the Turkish sentence?

Turkish normally drops subject pronouns when they can be understood from context or verb endings. This is called a pro-drop language.

In this sentence, arkadaşım is clearly the subject of memnun, and the possessive on söyleyebildiği also shows who the subject is. So adding o (he/she) is unnecessary:

Arkadaşım, fikirlerini özgürce söyleyebildiği için memnun.
= perfectly natural
O, arkadaşım, … would be odd and redundant here.

English needs the pronoun; Turkish usually does not.

Why is memnun alone, without olmak or a verb like “to be”?

In Turkish, with 3rd person singular/plural, the copula (“to be”) is often not written when using adjectives or nouns as predicates in the simple present.

O mutlu. = He/She is happy.
Arkadaşım öğretmen. = My friend is a teacher.
Arkadaşım memnun. = My friend is pleased.

Here, memnun is an adjective meaning pleased / glad / satisfied. You could add olmak in some tenses or for emphasis:

Arkadaşım … memnun oluyor. = is becoming pleased / keeps being pleased
Arkadaşım … memnundur. = is (indeed) pleased (more formal/emphatic)

But in everyday language, memnun on its own at the end of the sentence is the normal way to say “is pleased.”

What is the difference between memnun and mutlu?

Both relate to positive feelings, but their usage is a bit different:

mutlu = happy (more general emotional happiness)
memnun = pleased / satisfied (often with a specific situation or result)

In this context:

Arkadaşım, fikirlerini özgürce söyleyebildiği için mutlu.
= My friend is (emotionally) happy because he/she can express opinions freely.
Arkadaşım, fikirlerini özgürce söyleyebildiği için memnun.
= My friend is pleased / glad / satisfied (about this fact).

So memnun fits well when you’re pleased because of a particular condition or opportunity (like being able to speak freely).

Could we say “söyleyebildiğinden memnun” instead of “söyleyebildiği için memnun”? What’s the difference?

Yes, that’s also grammatically correct:

Arkadaşım, fikirlerini özgürce söyleyebildiğinden memnun.

Here:

…söyleyebildiğinden = “from/because of his/her being able to say (them)”
- -den/-dan is the ablative case (“from, because of”).

Difference in nuance:

…söyleyebildiği için memnun
→ very straightforward “(he/she is) pleased because (he/she) can say them”.
…söyleyebildiğinden memnun
→ more literally “(he/she is) pleased about/from the fact that (he/she) can say them”, slightly more compact, maybe a bit more formal in some contexts.

Both express a cause; “…diği için” is more transparently “because”.

Is the word order fixed? Can we move parts of the sentence around?

Turkish word order is relatively flexible, but the verb/predicate usually comes at the end. In your sentence, memnun is the predicate, so it stays at the end.

You could rearrange for emphasis, mainly within the reason clause:

Arkadaşım, özgürce fikirlerini söyleyebildiği için memnun.
Arkadaşım, fikirlerini söyleyebildiği için özgürce memnun. (this one is odd; özgürce should modify söyleyebildiği, not memnun)

Natural variations keep:

the main structure: [subject], [reason clause] memnun.
the predicate memnun at the end
özgürce close to söyleyebildiği (the verb it modifies)

A commonly used alternative wording with çünkü:

Arkadaşım memnun, çünkü fikirlerini özgürce söyleyebiliyor.

Can we use demek or konuşmak instead of söylemek here?

Not naturally in this exact structure.

söylemek = to say, to tell (something specific)
demek = to say (often used with direct quotes: “X dedi”)
konuşmak = to speak, to talk (more general)

Here we are talking about expressing specific opinions, so fikirlerini söylemek (“to say/tell one’s opinions”) is the idiomatic choice.

You could rephrase using konuşmak:

Arkadaşım, fikirleri hakkında özgürce konuşabildiği için memnun.
= My friend is pleased because he/she can speak freely about (his/her) opinions.

But simply substituting demek or konuşmak into the original sentence would sound unnatural.