What is the meaning of prefix -y in the following examples? [duplicate]

Solution 1:

A past participle form from Old English ge-:

Y- :

The prefix ge-, a regular past participle marker in Old English, continued to be attached to the past participle throughout the Middle English period. Over time, however, the attachment of ge-, which weakened to a form spelt y- (or i-), be- came no longer obligatory. The Northern dialects eliminated the prefix, leaving suffixes as the sole markers of the past participle. In the South, y- was still used, but optionally, especially in Late Middle English, with a steady increase in the use of forms lacking prefixal marking.

(www.peterlang.com)