Re’uel or De’uel?
Moshe appointed 12 tribal leaders to help count the people. The representative of Gad is called: “Eliasaph ben De'uel” in chapter 1:14, and “Eliasaph ben Re'uel” in Chapter 2:14.
Why is Eliasph’s father’s sometimes called: “De’uel” (with a daled – "ד") and sometimes “Re”uel” (with a resh "ר")?
Modern commentators do not have a problem with this, after all the only difference between a daled and a resh ("ד" and "ר") is that the daled’s head runs slightly over the vertical line. Therefore, at some point a scribal error occurred and the name was recorded incorrectly. Alternative manuscripts of the Bible seem to confirm this.
However, orthodox Jews tend to dislike this type of answer. The ancient scribes revered the Torah and were very diligent in the way they copied it. Indeed, the fact that ancient Torah manuscripts barely differ from what we have today, illustrates how careful they actually were in recording the words.
I would therefore like to offer two alternative explanations. The Ramban explains that the Torah often changes the name of people to a different name with the same meaning.
For example, in Bemidbar 26:13 we see a gentleman called Zerach. However, in Bereshit 46:10, he is called. Zochar. “Zerach” and “Zochar” both have the same meaning, i.e. “shining light”. Therefore, he was known by both names and so the Torah uses both.
So too, De’uel and Re’uel. Both names mean: “One who is close to God”. Thereby, he was known by both names.
The English language has it’s own equivalent: Rob and Bob, Will and Bill and Richard and Dick. People with one of those names are also called by the alternative name.
Moshe Cassuto, professor of Bible at the Hebrew University, suggests an alternative answer. Bereshit Chapter 10 records the lists the nations descendent from Noach. In passuk 4 we are told of the descendents of Yavan: “The sons of Yavan were Elishah and Tarshish, Kittim, and Dodanim”. However the “Dodanim” are called: “Rodanim” in Divrei Hayamim I 1:7: “The sons of Yavan were Elishah, and Tarshish, Kittim, and Rodanim”.
Once again we have a “daled” and a “resh” interchanged. He suggests that the original name of the people was “Derodanim”, however, they were known better in its shorter form, as both the Dodanim and the Rodanim. So too, Eliasph's father. His full name was Deru’el. However, he was called by both its shoerter forms; sometimes called De’uel and sometimes Re’uel.