Second person always plural in ordinary English.
79. Thou, thee, etc., are old forms which are now out of use in ordinary speech. The consequence is, that we have no singular pronoun of the second person in ordinary speech or prose, but make the plural you do duty for the singular. We use it with a plural verb always, even when referring to a single object.
Two uses of the old singulars.
80. There are, however, two modern uses of thou, thy, etc.:—
(1) In elevated style, especially in poetry; as,—
With thy clear keen joyance
Languor cannot be;
Shadow of annoyance
Never came near thee;
Thou lovest; but ne'er knew love's sad satiety.
—Shelley.
(2) In addressing the Deity, as in prayers, etc.; for example,—
Oh, thou Shepherd of Israel, that didst comfort thy people of old, to thy care we commit the helpless.—Beecher.
The form its.
81. It is worth while to consider the possessive its. This is of comparatively recent growth. The old form was his (from the nominative hit), and this continued in use till the sixteenth century. The transition from the old his to the modern its is shown in these sentences:—