In other languages if one wanted to say "I want to go" or "He needs to buy", the infinitive form of the second verb would be used (i.e. "to go" or "to buy"). To say these phrases in Romanian the speaker must use a form called the subjunctive. Speakers caught not using the subjunctive are usually dragged into the street and beaten with clubs (ciomege).

Examples of the subjunctive:
Trebuie să mergem la Bucureşti. We have to go to Bucharest.
Nu pot să vorbesc ungureşte. I cannot speak Hungarian.

As you can see, the subjunctive is "să + present tense". Just as with the normal present tense, the subjunctive is conjugated so personal pronouns are unnecessary.

Trebuie să merg	I have to go
Trebuie să mergi	You have to go
Trebuie să meargă	He/She has to go
Trebuie să mergem	We have to go
Trebuie să mergeţi	You (pl) have to go
Trebuie să meargă	They have to go

("Trebuie" is like the French "il faut", meaning "it is necessary").

You may notice that the 3rd person form (meargă) is a bit different than the normal 3rd person present tense (merge). This change in the 3rd person form will be common when forming the subjunctive, but everything else stays the same.

The rules for this change in the 3rd person are fairly simple. Here are the rules and some examples using "merge", "întreba", and "vorbi"; meaning "to go", "to ask", and "to speak", respectively.

Change	Condition	Example
e -> ea	middle of word	merge -> meargă
e -> ă	end of word	merge -> meargă
ă -> e	end of word	întreabă -> întrebe
ea -> e	middle of word	întreabă -> întrebe
eşte -> ească	end of word	vorbeşte -> vorbească

Constructions using the subjunctive are usually started with "putea", "vrea", and "trebui". Here are some example sentences containing the subjunctive.

Pot să scriu foarte bine. I can write very well.
Nu poţi să citeşti prea bine. You cannot read too well.

Trebuie să vorbim cu el. We need to speak with him.
Trebuie să vorbească cu noi. He/She must speak with us.
Nu trebuie să plecăm mîine. We don't need to leave tomorrow.
El trebuie să plece în seara asta. He needs to leave tonight.*
Ea trebuie să plece mîine seară. She needs to leave tomorrow night.*
* The personal pronoun is used here to avoid ambiguity, as "să plece" can imply "he", "she" or "they".

Vreau să merg la Oradea. I want to go to Oradea.
Vreau să mergi la Oradea. I want you to go to Oradea.
Vrem să mergeţi la Oradea. We want you all to go to Oradea.