what is the nostalgia in the poem "the solitary reaper"?

This is one of Wordsworth's most lyrical poems. Many scholars link it to Wordsworth's tour of the Scottish Highlands. The pastoral delights he felt there are reflected in his poem. His memory of the place reminded him that God, “rolls through all things.” Wordsworth waxes nostalgic about pretty much everything he sees. The lone girl he sees becomes the flaxen angel-like figure, “Behold her, single in the field/…….Reaping and singing by herself/ Stop here, or gently pass!” The poem goes on like this embellishing each moment as a memory never to be replicated.

the nostalgia is that the poet does not understand the language