When Psychic types “talk” to humans, do they have their own voices and accents or do they just sound like that little voicr in you hear

It depends on their level of mastery over telepathy, actually. Younger, less powerful pokémon tend to sound exactly as they do when speaking aloud. That is to say, an abra’s words will sound like an abra’s barks do to your ears. 

As they get older or more powerful, however, they gain the ability to replicate different voices, and thus, they sound however they feel like sounding. Some of the most powerful pokémon, I’m told, tend to use deeper voices, occasionally with accents seen as being “high class” to humans, all in an effort to instill an appropriate level of respect. For another example, my own kadabra most often reminds me of my grandfather’s voice: bass, smooth, and with an accent much like my own. Amanita’s munna, conversely, often “speaks” with a high-pitched, feminine voice, even though the munna is actually male.

In general, though, psychic pokémon make an effort to avoid using your voice when it speaks. This is for two reasons. First and foremost, using your voice increases the risk that you mistake what they have to say for your own inner thoughts, leading you to inadvertently ignore them. Second, it doesn’t exactly do wonders for one’s emotional stability, no.