Laguages associated to Barbarian peoples, Gothic, Burgundian, Vandalic, Alan, etc. essentially disappeared as everyday languages by the late Vth and early VIth centuries except as ceremonial and identitarian features (critically in onomastics, legal and political features etc. not unlike Latin in XIXth century courts).

Frankish, or rather probably a set of related but distinct Germanic speech and not an unified language, was a bit distinct there because Franks settled regions with a strong Germanic presence since the IIIrd century along the Rhine. In these regions, on a long time between the IIIrd and Xth centuries, Roman and Germanic seeches co-existed with a growing importance of the latter, while it is barely noticable in the rest of Gaul as soon as the VIth outside the aformentioned features.

Still, Romanized Franks (or "Frankishified Romans" as well) had a basic understanding at least of Frankish to both determine the meaning of Frankish names, or even transform their own names (such as a family of Lupii, whose a member eventually elected to name himself "Wulf"; or a kinsman of Gregorius of Tours adopting the name "Gondulf"). Besides the adption of "fashionable" names either by translating them or taking them because it had a nice ring to it (which happened both ways, Ansegisel being likely a transliteration of latin Anchises) there was a genealogical logic into onomastic make-up and transmission.

Names, indeed, served to establish a genealogical link between persons by decomposing and recomposing radicals : Hlod-wig (Clovis) and Hlod-hild (Clotild) were thus aptly named Hlod-mir (Clodomir) Hild-bert (Childebert) Hlod-hart (Clothar). Eventually, the radicals Hlod- and Hild- became strongly associated with Frankish kingship, and thus regularily used as were -bert.

That wasn't the only feature factoring in a name however : the first son of Clovis, Theudeuric, likely owes his name to Theodoric the Great, born as Clovis entered in a pseudo-genealogical relation with a prestigious Ostrogothic king (the radical Theud- eventually entering in royal onomastics). Likewise, prestigious names could be entierely recycled to make a point (later, Charlemagne gave to two of his sons Merovingian names : Louis or Clovis, and Lothar or Clothar).

Note that we're talking about royal and aristocratic names there, not just in genealogical or social, but also political sense : Merovingian sons that had to be consecrated to the church were named with vetero-testamentary names (such as David). That being said, "royal" radicals weren't limited to Merovingians : important aristocratic families could use them as well, as it carried either a sense of closeness and trust, either simply a prestigious implication, Merovingians remaining overall popular among Franks until their end.

Eventually, radicals or names could exist outside genealogical or prestige reasoning : there's no evidence that Daga-bert (Dagobert) owes the first part of his name to his ascendency (altough it could come from batism). It could carry some prestigious meaing as he was the main heir, or simply sounds right. This usage wasn't particularly Frankish : you can find a taste for alliterations and transmitted radicals in Saxon England, Ostrogothic Italy, etc. (as well as in .J.R.R. Tolkien's works).

Rather than "clumsiness", which is eventually coming from from historical prejudice on Franks in particular, Barbarians in general, as unable to even understand their own names, we'd rather have a complex set of onomastics which served to both identify an individual genealogically and socially but as well to make a symbolical point as the old Roman naming habits had disappeared.

It was particularily important because, as far as we know, there is absolutely no evidence of heraldy or proto-vexillography in Francia. The closest thing you could have of a specific banner would be the banner of Charlemagne depicted in this restored mosaic, linkening Charlemagne to Constantine or the use on Carolingian illustrations of the draco by Franks. Both are made, however, in a context of archaising representation of armies and displays, and not really sure to represent a contemporary reality.

Now, what about Peppinids?

Well, the first thing to understand is that the lineage we call Peppinid...wasn't really peppinid. The "true" Peppinid line emerged with Peppin the Elder, an Austrasian aristocrat of the late VIth century : we don't know who were his ascendents (maybe someone called Carloman) except they were famous. Giving the radical Grim- of his descendent and kinsmen, there were maybe ties with Bavarians or Lombards "cariried" over into familial onomastics. His son Grimoald attempted...something about the Merovingian succession we don't really know the details about apart it involded someone adopting someone between two lines (more probably Grimoald adopting a Merovingian prince than the contrary) which failed to the point Peppinids were ousted and killed out of power.

Eventually a lineage related to Peppinids by marriage, called Arnulfians (as descending from Arnulf of Metz) more or less inherited Peppinid aristocratic network, but as well prestige and onomastics. And,thus, names as Peppin or Charles made their way into the dynasty.

Did Peppinids took a care at the specific meaning of these names? Maybe, maybe not : eventually, it wasn't hugely relevant as they gave up the genealogical puzzle make-up of names (or, rather, Merovingians seems to have already done so in the VIIIth century) , rather considering them as whole dynastic markers (something that continued into the Middle-Ages, with Louis for Capetians, Raymond for the House of Toulouse, etc.) altough they certainly knew what the names meant at least until the Xth century.

Did lower classes used Frankish names? It probably depended from various factors : how quickly local elites adopted Frankish social codes, identity and onomastics; or the popularity of new saints (and, indeed, there was an explosion of sainthood in Gaul during the Merovingian era) or the establishment of monasteries often led by the same elites, etc.

What we know of lower classes naming usually involves "Christian" or simple Frankish names (such as Tudo, Bobo, etc.) which both declined in use in favor of Biblical and double Frankish names (we saw restricted to aristocracy at first, then quickly popularised by the VIIth century). Now, popular names weren't really recorded over, so it's quite possible there's evolutions or conservatism we don't know about.

Localism and local trends, however, seems to have played a really important role, altough many names taken from local saints or prestigious persons mostly last for one or two generations, local onomastics and influences colours the use of Frankish-related names (for exemple, Gothic onomastics in Languedoc.