Feast of the Nativity of John the Baptist

The chants and texts for the feast (including a listing of the proper psalms) other than the readings can be found in the Liber Responsorialis (download from CC Watershed) from page 345.

Translations and notes on other sources for the responsory chants can be found under the label JohntheBaptistnav.

Translations of the readings can be found in the Liturgical Readings book - not all of the readings for the feast are available online, but those that are can be found arranged as for the Benedictine Office  on the Lectio Divina Notes blog.