Slovenian is the official language in Slovenia. Border-regions are bilingual: here, Italian, German, Hungarian and Croatian can be spoken. Especially younger Slovenes usually speak English as a second language.
The Euro is used as official currency in Slovenia. Other currencies are generally not accepted. Money can be exchanged at banks, alternatively, it can be retrieved at ATM machines. You can find ATM machines in shopping centres, at banks and at the larger petrol-stations. Some smaller shops still accept only cash. For any seller (shop, restaurant etc) it is obligatory to give you a bill.
Tipping is not an obligation in Slovenia, but it is welcomed. Prices in shops are non-negotiable.
In Slovenia the power sockets are of type F. The standard voltage is 230 V and the standard frequency is 50 Hz. Note that this is much higher than, for instance, in North America. American devices may burn through and cause power shortages when they are used without an adaptor.
Generally, there are few power sockets in a room, but electricity should be available. Note that the light-switch of a bathroom can be located outside the bathroom, besides the door.
Slovenia uses the Central European time, UCT + 1.
There is a one-hour difference between summer- and winter time:
Sunday, 31 March 2019, 02:00:00 clocks are turned forward 1 hour to 03:00:00 local daylight time instead.
Sunday, 27 October 2019, 03:00:00 clocks are turned backwards 1 hour to 02:00:00 local standard time instead.
There are several mobile-phone providers and a telephone signal should be available in all inhabited places. However, especially in steep mountain valleys, you may find yourselves without telephone signal.
The international dial-code for Slovenia is ++386
Public telephones have practically disappeared in Slovenia because it is assumed that everyone has a mobile phone.
Most accommodations in Slovenia offer free WI-FI to their guests, however, sometimes there are issues with a too low capacity. Generally, it should suffice for e-mail and some information searching online, but downloading movies may be problematic in some places.
Stamps (for letters and postcards) can only be bought at post offices.