Be careful of the person who needs something. In Turkish, we will almost always attach it to the verb as a personal suffix. A few of these attach to the "need" word, but not all. Because they are the owners of a verb, what is the subject in English becomes a possessor in Turkish. For example:
Sizin Türkçe daha fazla konuşmanız gerek.
= You need to speak more Turkish. (Literally, Your speaking more Turkish is necessary)
You don't need to include Sizin in the last sentence, but if you do include, it must be possessive Sizin and not Siz.
As you probably know, -mak/mek is the Turkish infinitive. This is the ending you will see if there are no other endings attached. However, once you add any personal ending (ex: -m, -n, -sı, -mız, -nız) or any noun case (ex: -ı, -a, -da, -dan, -la), that ending -k is dropped. However, in the absence of any ending, the Turkish verb can keep -mak/mek.
Remember that if you want an impersonal need, you can do that by not adding any personal ending and keeping that infinitive -mak/mek. In English, we would have to change the verb to passive or use a unique adjective like "necessary" to denote impersonal necessity. In Turkish, impersonal is the default, and we must add person by adding a personal suffix.
Arabayla gitmek gerek.
= It is necessary to go by car. (impersonal)
Arabayla gitmen gerek.
= YOU have to go by car. (personal to you)
When choosing your Turkish ending, try to keep in mind if you are using impersonal you or the actual 2nd person YOU. It might be identical in English, but it can be different in Turkish.
Something else to keep in mind before listing all these words is what part of speech you need. Do you need a noun or a verb? For example, I need water vs. I need to drink water. This will help you narrow down what you want to use.
-ma + personal ending + gerek
This one is very flexible because gerekmek is also a verb meaning to be necessary/to be needed, to which you can attach time suffixes.
Bugün çamaşır yıkamam gerek. / Bugün çamaşır yıkamam gerekiyor.
= I need to do laundry today.
Yarın meşgul olacak mısın? Bana yardım etmen gerekecek.
= Will you be busy tomorrow? You'll need to help me.
Bu sabah çok erken uyanmam gerekti. Bu yüzden çok yorgunum.
= I had to wake up so early this morning. That's why I am so tired.
Be careful to not put the personal suffix on gerek.
-ma + personal ending + şart
This word originally means "condition," so this affects how we use it. It's an adjective that means "necessary" or "needed," so just like gerek, we don't add a personal suffix onto şart but onto the verb. Because of its meaning of condition, this adjective must be with a nominal verb; you cannot use a noun. A noun is not a condition; a verb is a condition.
Her gün Türkçe öğrenmemiz şart.
= We need to learn Turkish every day.
Dışarı çıkmadan önce anahtarım bulmam şart.
= I need to find my key before I go out.
-ma + personal ending + lazım
This word has the same meanings as all the others. It is grammatically the same as şart; you should use verbs with personal suffixes and no suffix on the adjective lazım.
Bu kitabı okuman lazım.
= You should read this book.
Meyveler ve sebzeler daha fazla yemem lazım.
= I need to eat more fruits and vegetables.
verb + -meli/malı- + personal ending
This is not a word. This is an affix. More specifically, it is an infix that you put in the middle of the word with a verb root before and a personal ending after. This can only be attached to verbs.
Üşüdüğümde sıcak çay içmeliyim.
= I have to drink hot tea when I am cold.
Çok Türkçe kelimeleri hatırlamalısın.
= You have to remember a lot of Turkish words.
-ma + -ya/ye + mecbur + personal ending
The meaning is the same on this one, but the syntax has changed a lot. Again, we need a verb with -ma, but it does not get a personal ending. It gets a dative ending -ya or -ye. This is one of the most common ending when adjectives connect to complements in Turkish. I've written about it on this blog before. Then, we have the adjective mecbur, which gets the personal ending.
Dersten önce bu kitabı okumaya mecbursun.
= You have to read this book before class.
Türkiye'ye geldiğinde Kapalıçarşı'ya seni götürmeye mecburuz.
= We have to take you to the Grand Bazaar (Kapalıçarşı) when you come to Turkey.
-mak + zorunda + personal ending
This one is unique but closer to the last one. This cannot really be translated properly, so just focus on the syntax. You must use the infinitive form of the verb without any personal ending. Then, zorunda is another word. Then, you add the personal ending to zorunda, just as if it is a location like okuldayım (=I am at school).
Saat 12'dan önce uyuyakalmak zorundanız.
= You need to fall asleep before 12 o'clock.
Video oyunu oynamak isterse önceden ev ödevini bitirmek zorunda.
= If he wants to play video games, he has to finish his homework beforehand.
noun + -ya/ye + ihtiyaç + personal ending + var
What if you want to say that you need to have something? In English, we can use need with any noun and it sounds natural: I need water, time, space, etc. However, as you know, Turkish is very particular with var and yok.
The person who needs (the subject in English) is the personal ending of ihtiyaç, and the object of necessity (the object in English) is before ihtiyaç with a dative case ending. As you probably know the oddities of var and yok, again the person who is in need is the possessor of ihtiyaç and therefore gets a genitive ending -ın/nın.
Köpeğimin çok yardıma ihtiyacı var.
= My dog needs a lot of help.
Bana sınıf nerede olmayı gösterecek birine ihtiyacım var.
= I need someone to show me where the classroom is.
noun + -ya/ye + ihtiyaç duymak + personal ending
This one is used in the situation of needing a noun or needing to have a noun. To talk about needing a noun, you need this construction: use a noun in the dative case and then ihtiyaç duymak conjugated for person.
What is special about this one is that this is the only one you can nominalize needing something. If you want to make a comment like "It's normal to need to study" or "She talks about needing a guide dog."
Yeni arkadaşlara ihtiyaç duyuyorum.
= I need new friends.
Yardıma ihtiyaç duymayı sevmiyorum.
= I don't like needing help.
Dünyayı kurtarmak istersek daha az ihtiyaç duymayı öğrenmeliyiz.
= If we want to save the world, we need to learn to need less.
Read the full post on my blog.