While Romania may be in eastern Europe, its language is not Slavic in origin. Rather, it is the only country east of Latin Europe that speaks a Romance language. This developed from when the land of what is now Romanian was under Roman rule. The people served in the Roman army, and Romans intermarried with the people. This caused the Latin language to become ingrained in the land's culture. This Romance base makes the language more approachable to speakers of English than the Slavic languages of the region.
Subliminal tapes work on the same principals of subliminal messaging: sending signals that you cannot consciously perceive, but your brain processes at the subconscious level. This principal was introduced in the 1950s when a psychologist, James Vicary, reported an experiment in which he flashed messages about buying drinks and popcorn on the screen at a movie theater while a movie was running. The messages were shown for only fractions of a second, so he claimed they could only be processed by the subconscious part of the brain. He reported that the theater's sales of drinks and popcorn increased significantly.
A number of tapes on the market claim to use subliminal messaging to help you learn Romanian. The method they advertise is not that the tapes will teach you the language themselves, but rather that they will help make learning the language through other tools easier. According to the tapes, they emit inaudible sounds that you cannot hear, but are still processed by your subconscious. These sounds are supposed to stimulate your brain in ways that will ease the difficulty of retaining Romanian words and grammatical structures.
Vicary's results caused a stir when he introduced them. People panicked about the possibility of subliminal messages affecting their behavior, and many governments banned the use of subliminal messages in advertising. However, other psychologists were unable to replicate the results of Vicary's experiment. Even though his experiment was disproved, many people continue to believe, without any scientific evidence, that subliminal messages can have significant effects on human cognition. While subliminal tapes might help you learn Romanian, they won't replace other forms of instruction or immersion.