UPDATE: thanks to Dr. Noam Sienna, the translator here is identified as Menahem Gershon Glenn (1896-1978), a writer, journalist, and educator who was a member of Mikveh Israel and a teacher at Gratz College in Philadelphia. ---Seeking more information on Menahem ben Moshe Zeke'el, מנחם בן משה יחזקאל, who provided the English translation to a Sefardic siddur published by Hebrew Publishing Company in 1935.