The suffix -mannich can be seen as a grammaticalization of the indefinite numeralmannich, which means a couple of or several. The suffix only has the former meaning, i.e. 'a couple of'. The list of derivations with -mannich is limited. Examples are given in the table below:

The base form is often a noun that indicates a measure of time, distance, weight, etc., but other nominal bases are also possible to certain extent:

There are a few input restrictions, mentioned by Hoekstra (1992:83-84). Firstly, a noun ending in -mannich cannot be preceded by an adjective:

Secondly, a sentence in which the noun is followed by a complement is not allowed. An example of such an ungrammatical sentence is given in (a) below. The solution is to put the word ending in -mannich before the complement, as can be seen in (b):

If the base noun indicates a measure, like kroade barrow in (4a) below and hûndert a hundred in (4b), the complement also has to be moved to the right-hand side of the derivation with -mannich:

Most of the times, the formation with -mannich is used in combination with the indefinite article in a(n). According to Hoekstra (1998:89), it is probably best to see in rather as an extension of the base than as an article, since the construction cannot exist without it:

Alternatively, we could consider this as an example of construction-dependent morphology, as the indefinite article forms part of the nominal construction.

However, we can evoke a definite article by attaching a complement, as in

We then see that derivations with -mannich have neuter gender, determined by the suffix. In the example above, the base dei day.C day has common gender, which is overridden by the gender of the suffix.

The suffix -mannich originates from the expression in {noun} of {numeral} a {noun} of {numeral}. An example is in dei of trije a day of three about three days (see also The construction in N of Num. In older Frisian, the numeral in this construction could also be represented by mannich, as can be seen in the following quotation:

Later on, the small word of of got elided, and in this way nouns in -mannich came into existence.

The suffix -mannich does not alter the stress pattern of the base form: DEI day > DEImannich couple of days and minÚT minute > minÚTmannich a couple of minutes. In most cases, there are no extra phonological shifts either: the suffix can just be added to the base form, as in gûne [ɡunə] guilder > gûnemannich [ɡunəmɔnəx] couple of guilders. However, in wykmannich couple of weeks the final schwa of the base form wike [vikə] week has been dropped.

Formations with bases that are not measure nouns tend to become restricted to the written language nowadays. However, they can easily be replaced by another derivation with -mannich, i.e. stikmannich. Hence, instead of in boekmannich a couple of books we then get in stikmannich boeken a couple of books. This derivation with the semantically 'empty' base noun stik piece actually functions as an indefinite numeral: in stikmannich beammen a couple of trees, in stikmannich gebouwen a couple of buildings, etcetera. However, for many speakers also in stikmannich will be rather archaic. For them, it would be more common to use the connected construction in stik of wat {noun} a piece or what a couple of, as in in stik of wat boeken a couple of books.