It was Sir Cailein Mor Campbell's grandfather Dugald on Lochawe who is said to have been the first given the nickname "Cam Beul" since he apparently had the engaging trait of talking out of one side of his mouth. Cam beul means curved mouth in the Gaelic. This Duncan was so much loved by his family that they took his nickname as their family name and held to it even beyond Argyll.
The spelling of the surname (family name) was originally Cambel. Then when Robert the Bruce's son King David came to the throne as King of Scots he brought with him a number of Norman knights to whom he gave lands in an attempt to introduce Norman efficiency in administration. David had been at the English court and admired the Norman system of feudalism. The use of the spelling "Campbell" may perhaps have been as a result of Norman rather than Gaelic scribes attempting to write the Gaelic name.
The name Cambel was first used by the family in the 13th century. The first chief of the clan to appear on record as "Campbell" may well have been Sir Duncan of Lochawe when he was created Lord Campbell in 1445.
It is interesting to note that Einar Sigurdsson, Earl of Orkney (died 1020), was also called Einar Wry-Mouth. One possible modern medical explanation is a form of Torticollis (from the Latin torti, meaning twisted, and collis, meaning neck), or "wry neck", a condition in which the head is tilted toward one side (cervical rotation), and the chin (mouth) is elevated and turned toward the opposite side (cervical extension) thereby producing a "Cam beul" or curved mouth in some cases
This ancient Scottish name has its origins in a Gaelic nickname "Caimbeul", meaning "wry (or crooked) mouth", from "dam", bent or crooked, and "beul", mouth. That it was originally a nickname can be seen by a charter of 1447, which records Duncan le Cambeli, the first Lord Campbell, the "le" being the Scottish "lie", meaning "so called", or "known as". A sizeable group of early European surnames were gradually created from the habitual use of nicknames. These were given in the first instance with reference to occupation, or to a variety of characteristics, such as physical attributes or peculiarities, mental and moral characteristics, supposed resemblance to an animal's or bird's appearance or disposition, or to habits of dress. Clan tradition has it, that the Campbells were originally known as "Clana Duibhne" or "O'Duine", from one Diarmid O'Duine of Lochow. About 1390, Duncan Campbell witnessed a charter by Duncan, Earl of Levenax, and is believed to be the first namebearer to introduce a "p" into the name, influenced by the erroneous theory that "Cam(p)bell" comes from the Norman-French "de Campobello" i.e., "of the beautiful plain". Campbell is the family name of the hereditary Dukes of Argyll, dating from 1445, and their Coat of Arms is described thus: "Quarterly, first and fourth, gyronny of eight gold and black, the Crest being a boar's head couped gold". The first recorded spelling of the family name is shown to be that of Gillespic Cambel, which was dated 1263, in the "Exchequer Rolls of Scotland", during the reign of King Alexander 111 of Scotland, 1249 - 1286. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling