Many people have the practice to recite before performing a Mitzva the "Le'Shem Yichud" paragraph, in which one expresses his intention to fulfill the Mitzva for the sake of serving God and asks that the Shechina (Divine Presence) accompany him as he performs this Mitzva. This is a very worthy practice, in that it helps focus a person's attention on the Mitzva he is about to perform, and adds a dimension of speech to Mitzvot that otherwise do not include any verbal component.
The "Le'Shem Yichud" includes a passage in which one spells out the four letters of God's Name – "Yod," followed by "Hei," followed by "Vav," followed by "Hei." Now it emerges from a discussion of Tosefot in Maschet Sukkah (5A) that it is forbidden not only to articulate the Divine Name, but also to spell the letters. Therefore, one who recites the "Le'Shem Yichud" must ensure not to spell the letters in succession, without making some interruption between the letters. The Arizal (Rabbi Yitzchak Luria, renowned Kabbalist, Israel, 1534-1572), for example, would say "ee" in between each two letters. The Ben Ish Chai (Rabbi Yosef Chayim of Baghdad, 1833-1909) in Od Yosef Chai, Parashat VaYehi, Ot 26, writes that one can pronounce the letter "Hei" as "Kei," and then he may recite the letters in succession without any interruption. One may also simply insert the word "Ot" ("letter") before saying the name of each letter ("Ot Yod, Ot Hei, Ot Vav, Ot Hei"). (See Halichot Olam, Helek 1, page 49.)
As mentioned earlier, the purpose of reciting the "Le'Shem Yichud" is to help focus one's attention on the performance of the Mitzva. Unfortunately, some people recite the "Le'Shem Yichud" thoughtlessly, by rote, thereby undermining its entire purpose and function. One who recites the "Le'Shem Yichud" should do so with concentration, in order that it help him focus his mind on the fulfillment of the given Mitzva.
Summary: Many people follow the commendable practice of reciting the "Le'Shem Yichud" before performing a Mitzva. One who does so must ensure not to spell the four letters of God's Name without either making some interruption between the letters or reciting "Kei" instead of the letter "Hei," and he should make a point of reciting this paragraph with concentration, and not by mindless rote.