1. Yes, suffixes are very important. Teþekkür etmek is the verb form of "thank", teþekkür ederim is for "I" like "I thank you", teþekkür ederiz is for "we" like "we thank you". Teþekkür ediyorum is same for "I" but another tense, present continuous.

2. could be many teþekkürler is the noun form as an example.

3. Teþekkür ediyorum sounds like you will say more or something contrary/against to your thank but that is not a rule. just a sound/emphasize if that is used well. teþekkür ederiz is for "we", so if you are talking as a leader of speaker of someone, you may use it. teþekkürler and teþekkür ederim are same for me. sað ol is for some more close friends/people, informal type thank.

Dönüm saðýma: I turned to my right side

baktým soluma: I looked at my left side

yine sen: again you

not "health" sað and breath solumak. we say "nefes" or "soluk" for breath as noun and ver form is "solumak": soluyorum. it can be a conflict by "solmak" too, indeed we use "nefes almak" more

Thanks for sharing but is this about "Turkey"? I mean, I guess that is for "off-topic" more, isn´t it?

Indeed, there are two different statements (or sentences/clauses) in original one "Sorry, (comma) ..."

Akþam çok geç yazdým, (separate the clauses) özür dilerim

Kusura bakma, bilgisayar baþýnda deðildim.

if you say "bilgisayarýmda" it means in my computer" we say "bilgisayar baþýnda" for "at the computer"

a little child: küçük bir çocuk

the little one: küçük olaný

It depends what you are talking about as well

1. Dün gece moralim bozuktu, kusura bakma. Senin suçun deðil.

2. Hâlâ Mehmet´e mi gidiyorsun? (put the name instead of "Mehmet", I hope you know what vowel and cononant harmonies in Turkish are)

3. Bir nedeni yoktu

It depends on what you are talking about

You can use "bir" or "bir tek" to emphesize something emotional generally, before the word or the word group which you want to emphesize. And that word or the word group must be before the verb;

Ankara´ya bir tek senin için geleceðim

Bu konuda bir ben yanýldým

Yüzlerce þarkýnýn arasýnda bir bunu seviyorum