Why the person switches in Shemos 14:2-4?

Question

Shemos 14:2-4:

דבר, אל-בני ישראל, וישובו ויחנו לפני פי החירות, בין מגדול ובין הים: לפני בעל צפון, נכחו תחנו על-הים.‏

ואמר פרעה לבני ישראל, נבוכים הם בארץ; סגר עליהם, המדבר.‏

וחיזקתי את-לב-פרעה, ורדף אחריהם, ואיכבדה בפרעה ובכל-חילו, וידעו מצריים כי-אני יהוה; ויעשו-כן.‏

The first verse switches from third person to second person mid-verse (ויחנו is third person, תחנו is second person). The second and third verse revert to third person. (The second verse is not so bothersome, as it is paraphrasing what Pharaoh will say.)

Why the switches?

Answer 1

The Tur explains the change. נכחו is referring to the direction from which they approached, like in Yechezkel 46:9. תחנו is referring to the camping of the Jewish people.

Answer 2

Chabad.org translates:

דַּבֵּר אֶל בְּנֵי יִשְׂרָאֵל וְיָשֻׁבוּ וְיַחֲנוּ לִפְנֵי פִּי הַחִירֹת בֵּין מִגְדֹּל וּבֵין הַיָּם לִפְנֵי בַּעַל צְפֹן נִכְחוֹ תַחֲנוּ עַל הַיָּם:

Speak to the children of Israel, and let them turn back and encamp in front of Pi hahiroth, between Migdol and the sea; in front of Baal Zephon, you shall encamp opposite it, by the sea.

And Rav Levy (Rav Hirsch' grandson) translates into English from the German that Rav Hirsch translates into:

Speak unto the Children of Israel that they turn back and encamp before Pi-Hachiroth, between Migdol and the sea. In view of Baal-zephon, opposite it, shall ye encamp by the sea.

Thus, the first part is to Moshe giving the purpose of the command and the last part is the actual command as Moshe is to tell Bnai Yisrael.