Subjective clause adverbs express the speaker's subjective emotion or evaluation concerning the denotation of the clause, such as hope or happiness. They include the following: hopentlik ‘hopefully’, glukkelk ‘fortunately’, uunglukkelkerwieze ‘unfortunately’. They have a somewhat bookish character, and they are more characteristic of written language. Instead of hopentlik ‘hopefully’, it would be more natural to use the verb on which the adverbial is based, as in: ‘I hope that’. Similarly, instead of ‘fortunately’, it would be more natural to say ‘it is nice that’.

Evaluative or modal clause adverbs express modalities like possibility, probability, and so on. Modal clause adverbs include the following: ogenskienelk ‘apparently’, sääft ‘maybe, possibly’, toumäts ‘maybe’, woarskienelk ‘probably’. This have the form of APs. In some cases, there are semantic equivalents belonging to a different syntactic category. Probability and possibility are also expressed as VPs in kon weze ‘can be > maybe’, maiweze ‘could be > maybe’ and kuudweze ‘could be > maybe’. Fort writes the first of these three collocations as two words, the other two as one word. Another modal adverb is toumäts ‘maybe’, which also means ‘now and then’.

Time adverbs are in fact rarely of the category AP. Examples of time adverbials, all categories, include the following: nu ‘now’, do ‘then’, dälich ‘today’, mäiden ‘tomorrow, in the morning’, middai ‘at noon’, jäärsene ‘yesterday’, ättertied ‘afterwards, later’, äntelk ‘finally’, toulääst ‘lastly’. The following four expressions seem to belong together, perhaps as a square of opposition:

The form siläärge ‘still’ is found in a sentence like the following:

This word more commonly occurs in the negative collocation silläärge nit ‘never’. Time is questioned with the interrogative wanner ‘when’. Time adverbials also include expressions for the hours, the days of the week, the seazons and idiomatic expressions like twiske dän Middei ‘at noon’, ju Tuwwelkeskillertied ‘the ten o’clock coffee break’, and so on. Some time adverbials also function as frequency adverbials, such as aaltied ‘always’. The distinction between time and frequency is hard to make in some cases, since frequency takes place in time. In fact, frequency imposes a count character on our conceptualisation of time. If so, we must distinguish between non-count expressions of time (including expressions which are like proper nouns), which we refer to as time adverbials in the narrow sense, and countable expressions of time, which we refer to as adverbials of frequency.

Frequency adverbs provide information about the frequency of occurrence of events. Like time adverbials, frequency adverbs are usually Noun Phrases (NPs) rather than Adjective Phrases (APs). Examples of frequency adverbials are: gau ‘frequently’, gerägeld ‘regularly, insen ‘once, one day’ with its Low German interference moal ‘once, ever’ or eenmoal ‘once’, twäie ‘twice’, maasttied ‘most of the time’, säilden ‘seldom’, aalmantou ‘continually’ (interference or loan: immertou, eengoalwäg). The following four expressions fit into the square of opposition:

There is a relation between frequency and countability. Thus events can be numbered with the help of numerals, which may or must be followed by a dummy noun of frequency, such as mal ‘times’ in German or keer ‘times’ in Dutch. Saterland Frisian features moal ‘times’, as in the following examples:

The dummy noun of frequency can be preceded by ordinals to rank similar events, as shown by the example above. However, it is also possible to use a cardinal number, without a dummy noun, as in the following examples:

It seems, however, that only the numbers twäie ‘two’ and träie ‘three’ can be thus used. Furthermore, the form twäie ‘two’ is a distinct form of the numeral, exclusively used for frequency. To illustrate, consider the paradigm for these two numerals:

Table 1. Overview of three distinct forms of the numerals 2 and 3.

	MSC	FEM + NTR	Frequency
2	twäin	two	twäie
3	träi	trjo	träie

The schwa seems to mark a nominalisation of the numeral with a frequency interpretation. This type of frequency nominalisation is restricted to the numerals 2 and 3, much as in English twice and thrice. The numeral 1 has a frequency nominalisation in –n though: insen ‘once’. There is difference in meaning between insen ‘once’ and moal ‘once’. The former seems to be an existential quantifier of frequency, so it has a count character, whereas moal is an existential quantifier over time, where the distinction between count and mass is blurred. According to Fort, the collocation silläärge nit is a loan from Low German. This leaves open the question whether the meaning ‘still’ (see the section time adverbials above) is also a loan. Furthermore, it is unclear whether nooit ‘never’ is native to Saterland Frisian. The relative word order of time and frequency adverbials is such that time adverbials precede frequency adverbials in Saterland Frisian (but not in English). An example is given below:

Here the time adverbial specifies the time frame to which the adverbial of frequency, a nominalised numeral, applies.

Adverbs of emphasis provide emotional emphasis to the utterance. They include the following: jo ‘really’, apsluut ‘absolutely’, wuttelk ‘really’. No adverb of emphasis may occur in clause-initial position; instead they are restricted to the middle field. An example with jo ‘really’ is given below:

Adverbs of emphasis can hardly be fronted to the beginning of the sentence.