dát + Infinitive

The pattern dát (si) + infinitiv is an analytical causative construction. It is the exact functional equivalent of the English structure "to have/get something done". Note that personal services (like getting a haircut) specifically require the benefactive si when performed for oneself.

1. The Active Infinitive
Unlike English, which uses a passive participle ("had it translated"), Czech strictly requires an active infinitive. Because these are typically completed services, the infinitive is overwhelmingly perfective (e.g., opravit, přeložit). The object of the action takes the case governed by the infinitive, usually the accusative.

2. The Benefactive "si"
When the action is performed for the subject's own benefit, the dative reflexive pronoun si is added (benefactive si). This is highly common for personal services (dát si ostříhat vlasy). If si is used, it acts as a clitic and must occupy the second position in the clause. Crucially, do not place si after the infinitive due to English interference; it usually sits right after the conjugated verb and before the infinitive (correct: dám si ostříhat vlasy, incorrect: dám ostříhat si vlasy).

3. Dát vs. Nechat
In modern spoken Czech, nechat si + infinitiv (using nechat + infinitiv) is generally preferred for everyday personal causatives. Similarly, for non-benefactive causatives, nechat without si (e.g., nechal postavit dům) is the standard modern equivalent. Dát without si (e.g., dal přeložit smlouvu) carries a slightly more formal or literary nuance. Both verbs can also mean "to let/allow" (permissive), but they govern different cases: the person being allowed to perform the action takes the accusative with nechat (e.g., Nechal mě mluvit) but the dative with dát (e.g., Nedal mi mluvit). Furthermore, with a direct noun object, dát si means "to order" (dám si kávu = I'll have a coffee), whereas nechat si means "to keep" (nechám si kávu = I will keep the coffee).

4. The Agent
The actual person performing the work is usually omitted. If you need to specify them, the most natural and common way for personal services is to use the preposition u + genitive to mean "at the professional's place" (e.g., dát si opravit auto u mechanika, nechat si ostříhat vlasy u kadeřníka). You can also use od + genitive to specify the agent directly (e.g., dát si opravit auto od mechanika). A bare dative can also be used, but strictly only with non-reflexive dát (e.g., dal to přeložit překladateli). It cannot be used with dát si or nechat si, as Czech avoids double datives in this context.

5. Imperative Usage
This construction is highly common in the imperative for giving advice or commands to have something done. For example, Dej si ostříhat vlasy! (Get a haircut!) or Nech si to opravit! (Get it fixed!).