A myth of sorts has grown up around the idea that Jesus chose poor, uneducated fishermen to be his apostles. This idea is partly derived from Acts 4:13;
“Observing the boldness of Peter and John and perceiving them to be uneducated, ordinary men, they were amazed, and they recognized them as the companions of Jesus.”
These men were not generally aristocrats or trained scribes, but disciples of Jesus. The Greek agrammatoi can literally mean “without letters” or illiterate. In a religious context it probably has a more limited meaning of ‘not trained in the law’ (cf. John 7:15). In other words one not formally trained as a scribe. The Greek idiōtai literally means a private person, or an ordinary person as opposed to an expert.
In the ancient world eloquence or boldness of speech was associated with education or training in rhetoric. Since Peter and John are clearly untrained in these fields the boldness of their speech astonishes the Temple leaders. The Jewish leaders, “were amazed, and they recognized them as companions of Jesus” (Acts 2:13).
The ‘ordinary’ nature of these Apostles must not be exaggerated. M. Wilkins believes that "James and John" were from a family of some wealth and influence, based on the information we have about their fishing business (cf. Mk 1:19). Peter ran a fishing business with his brother Andrew and their partners, James and John (Mk 1:16-20; Luke 5:10) He seems also to have owned a house with his brother Andrew (Mk 1:29). Mark’s text suggest that the house was not far from the synagogue in Capernaum (compare Mk 1:21 with 1:29).
Luke’s comment in Acts 4:13 likely means that Peter, Andrew, James and John were merchants and not theologians by trade and of course they had no credentials as Scribes or Pharisees. Acts 4:13 could also have betrayed a prejudice against their Galilean accents or even against their very social class as "the newly wealthy" as opposed to the older aristocracy of the Sadducees. There is no indication here of them being poorly educated in general, semi-illiterate, or just plain dull. This does not fit their occupation or background, or the biblical record of their probable use of Greek.
Carsten Thiede comments, “an active knowledge of Greek would have been obligatory for people like Peter and his co-workers, Andrew, James and John (Mk 1:16; Lk 5:10), who were involved in the fishing industry and trade. They would have heard Peter speaking Greek from childhood days, and refined their linguistic abilities soon as they had chosen their trade. The Hellenistic element in their immediate surroundings is obvious even from their names.” Peter Davids notes that there was a growing group of wealthy merchants in first-century Palestine who had not yet joined the land owning aristocracy, and who did not have priestly or Herodian political connections. This group constituted as new addition to the wealth upper class. There was also "a small middle class of skilled artisans and land-owning medium sized farmers and merchants."
 Dictionary of Christ and the Gospels ed. Joel B. Green, Scot McKight, I. Howard Marshall (Downers Grove: Intervarsity Press, 1992) p. 179. If we identify the Apostle John as the beloved disciple (John 18:15) then we read the beloved disciple was "well known to the High Priest" signifying some upper class connections.
Ibid. p. 179. Are we to understand that James and John are also originally from Bethesda (cf. Mk 1:20)?
 Speaking to the Syrian Phoenician woman (Mk 7:26), a conversation with Pilate without an interpreter (Mk 15:2-5), the presence of Greek speaking Jews among the disciples (Acts 6:1), the meeting with Cornelius the Centurion (Acts 10:25-27).
 Carsten P. Thiede, Simon Peter: From Galilee to Rome (Academie Books, 1988) p. 20-21.
 Dictionary of Christ and the Gospels. p. 702.