Regarding the custom to turn over the tables on Shabbat HaGadol, the Shabbat right before Pesach. Speech remains in exile until Pesach. PeSaCh is Peh SaCh(a mouth speaking).¹⁴¹, Inyan Pesach #6; Likutey Moharan I, 49:6. On Pesach, speech emerges from exile. This is the main idea of the Exodus.

footnotes: ¹⁴¹ Sha'ar HaKavanot

The table connotes speech as it is written, “He spoke to me, this is the table that is before God” (Ezekiel 41:22).

“He spoke to me”: Regarding my food and sustenance - that is the table that is derived from the category of speech. Thus, it is written, “ From all that emanates from God’s mouth will man live” (Deuteronomy 8:3).

When speech is not in exile, then the table is turned toward us in an aspect of Face. “He spoke to me, this is the table that is facing (lifnei) God.” Lifnei literally means “towards the face of.”¹⁴² I, 67:2; Zimrat Ha'aretz, p. 105. When “He spoke to me,” then the table is in an aspect of Face or facing.

footnotes: ¹⁴² Cf. Likutey Moharan

Speech remains in exile until Pesach, until the Exodus. The tables are therefore turned over on Shabbat Hagadol, showing that speech is not yet in an aspect of Face. Speech emerges from exile only on Pesach — Peh Sach, “the mouth speaking.”