Śrāvakayāna (聲聞乘) is viewed from the perspective of Sarvāstivāda, and then Mahāyāna. These segregation of -yāna and -vāda came about after schisms in the Saṅgha, since ~100 years after the Buddha's death. Thick books on the history of the different traditions/sects of Buddhism have been written and published through the years - not a topic that could be dealt with in 三言兩語. For those who are interested, Indian Buddhism by A.K. Warder could be a good recommendation.
https://www.amazon.sg/Indian-Buddhism-K-Warder/dp/8120817419
Pacceka-
buddha (Sanskrit: Pratyekabuddha; Pratyekabuddhayana - 緣覺乘) are translated as Private Buddha, Silent Buddha, or Solitary Buddha. They attained liberation through their own effort, just like our Buddha Gotama. They appear during periods without Dhamma being made known, and they are not able to form a dispensation and teach the Dhamma, due to the absence of requisite conditions to do so. So, they are different from the Arahant disciples of the Buddha, who attained Arahantship after listening to and practising the Dhamma (聲聞); they are also not Sammasambuddha like Buddha Gotama, due to the reasons mentioned above.
It pays to remember this: the Buddha did not teach any
yāna or
-vāda; he taught the way to liberation. And the recipe/instruction manual is inside the 4 Noble Truths (1st discourse of the Buddha).