The Wiesbaden dialect belongs to the southern Hessian dialect area. The dialect-speaking group is relatively small, but is represented in all social classes. According to Günther Leicher (1923-2010), Wiesbaden citizens can be distinguished according to how they pronounce the name of the city in terms of their proximity to or distance from the dialect. Long-established residents call themselves "Wissbadner", while immigrants refer to themselves as "Wiesbaadener", i.e. with the emphasis on the third-last syllable. In between are the "Wiesbadeners", who occupy a neutral position between dialect and High German.

As a Nassau variant, the Wiesbaden dialect differs significantly from the other southern Hessian dialects spoken in Mainz, Frankfurt am Main or Darmstadt. Letters at the end of words are often swallowed, especially in verbs. So it is "lache" instead of laugh, "esse" instead of eat etc. Inside words, the "r" is omitted, so the name Karl becomes "Kall". The "st" and "sp" become a voiced "sch" with a soft consonant, e.g. "schbizz" for sharp and "schdolbern" for stumble. Ch or g, especially at the end of a word, becomes sch, "goldisch" for golden, "ferschderlisch" for terrible, "Grieschisch Kabell" for Greek chapel, etc. Ei and au often become an elongated aa, e.g. "Staa" for stone, "aaner" for one, "aach" for also. Hard consonants become soft, t becomes d, p becomes b, e.g. "Budding" instead of pudding; in addition, vowels are often stretched, so chocolate becomes "Schoggelaad".

In addition, there are numerous terms that are specific to this dialect, such as "Hackesjer" for a child's first teeth, "Hannebambel" for a man who is under the slipper, "Zores" for the urban underclass and idioms. Also typical is a tendency to use tautological expressions such as "e Fläschje Flaschebier" for a bottle of beer or "Schiffschebootsche" for a small passenger ship such as the "Tamara", which runs between Schierstein and the Rettbergsaue.

The Wiesbaden dialect poet Franz Bossong dedicated himself to the preservation and transmission of the language of the old-established citizens. In the 20th century, dialect poetry in Wiesbaden was strongly influenced by Rudolf Dietz, who was born in Naurod near Wiesbaden. Around 1900, the Wiesbaden Language Association, under the honorary chairmanship of Konrad Duden, also devoted itself to the cultivation of the Nassau dialect.

Currently, more than a third of Wiesbaden's urban population (as of 2015) has a migrant background. In the 19th century, Wiesbaden's upper class was shaped by wealthy newcomers who were far removed from the dialect, but the dialect remained firmly anchored in the lower class due to the influx of workers from the Nassau dialect areas of the Taunus and Westerwald as well as from Rheinhessen. This fostered the view among the educated classes that dialect was an underclass language that had no place in higher educational institutions and social life. Those who had moved to Wiesbaden since the end of the Second World War came from distant parts of Germany without any connection to the Nassau dialect, while the later labor migrants came from southern Europe and Turkey, i.e. from foreign language areas. Until the 1970s, it was possible to observe that migrants sometimes adopted the dialect through contact with native work colleagues and neighbors, but since around the end of the 1980s, it seems that the younger generations with a migrant background have tended to develop their own youth language with some foreign accents, but without a dialect.

Today, dialect has lost its reputation as a "lower class language". It is considered humorous and witty. Dialect is still spoken in established Wiesbaden families. The Wiesbaden dialect has a firm place in social life, especially at carnival. But there are also regular dialect articles in the Wiesbaden press. Günther Leicher made a special contribution to the preservation and communication of the Wiesbaden dialect in the present day with his "Wissbadner Wödderbuch" and with his "Schorsch vom Michelsberch" column in the Wiesbadener Tagblatt, which continued until his death. The Nassau dialect is more common in the rural surroundings of Wiesbaden. Rudolf Dietz and his work are still popular with the predominantly conservative population of some of Wiesbaden's eastern suburbs, especially in his birthplace of Naurod.