Odd word order for German modal verbs

When I started learning German to a reasonable level, I was puzzled by 2 oddities in how modal verbs work.

I’ll start by giving some background.

In German main clauses, the finite verb appears in 2^nd position (example 1). A finite verb is a verb form that marks the person and number of the subject— in example 1, the verb is marked as 3^rd person singular.

(1) er  tut    es
     he does it

In the perfect tense, the finite verb is the auxiliary—usually haben (‘have’), but for a few verbs it is sein (‘be’). The auxiliary appears in 2^nd position, and the past participle of the main verb appears at the end of the clause (example 2).

(2) er  hat es getan
     he has it done
    ‘he has done it’
(often better translated in to English as ‘he did it’)

Modal verbs

The main modal verbs in German are können (‘can’), müssen (‘must’), dürfen (‘be allowed’), sollen (‘shall’), wollen (‘will’), mögen (‘may’).

Like other finite verbs, modal verbs appear in 2^nd position and the infinitive of the main verb appears at the end of the clause (example 3).

(3) er  kann es tun
     he can    it  do
    ‘he can do it’

Now let’s look at the equivalent of example 3 in the perfect tense:

• the auxiliary hat (‘has’) appears in 2^nd position;
• the infinitive of the main verb tun (do’) appears in penultimate position; and
• the modal verb kann goes at the end (example 4).  

(4) er hat es tun können
     he has it  do  be.able
    ‘he could do it’, meaning ‘he was able to do it’

Example 4 shows one way English modals (such as can) differ from their German counterparts:
– the English modals have no infinite and no participles. When English wants to use an infinitive or participle for the modal can, English resorts to the phrase ‘be able’, producing ‘to be able’, ‘being able’ or ‘been able’.
– in contrast, the German modals do have infinitives and participles. For example, können (‘can’, ‘be able’) has the infinitive and it has a past participle (gekonnt).

The 1st oddity

Example 4 is where the first oddity shows up. The form of the modal verb kann at the end is not what we might expect—the past participle (gekonnt). Although that past participle is used in a limited range of cases with a noun complement, it is never used with a verbal complement (such as tun in example 4). Instead, the infinitive können is used. The same happens with the other modals.

German grammarians call the infinitive used in this way the Ersatzinfinitiv (‘replacement infinitive’) because the modal’s infinitive replaces the past participle that we would otherwise expect. German’s close relative Dutch has a somewhat similar construction, often known as IPP (infinitivus pro participio, ‘infinitive for participle’).

Digression: a different sentenc pattern

Before moving on from main clauses, I will look briefly at another construction. In example 4, the main verb and modal together describe a possible event (‘able to do it’) and the auxiliary hat marks the modal as referring to a possibility that existed in the past (‘was able to do it’). However, in example 5:

• the past participle of the main verb (getan) and the auxiliary (haben) together create an expression referring to a past event (‘has done / ‘did it’); and
• the modal indicates that it is possible that the event in fact occurred (is possible that has done / did it’.

(5) er  kann es getan haben
     he can it done have
    ‘it is possible [that] he has done it / did it’

Summary: main clauses

Table 1 summarises the positions of the finite verb, auxiliary and modal in main clauses. The items shown there are:

• FV finite main verb; FV.Aux: finite auxiliary verb; FV.Mod: finite modal verb
• PP: past participle (of main verb)
• Inf: infinite of main verb; Inf.Mod: infinite of modal verb; Inf.Aux: infinitive of auxiliary verb
• X: exactly one item
• X*: one or more other items

Table 1. Word order in main clauses

Subordinate clauses

I now turn to subordinate clauses. In such clauses, the subordinating conjunction (eg dass ‘that’) appears at the beginning of the subordinate clause, and the finite verb appears at its end (example 6).

(6) … , dass er  es tut
that he it does
          ‘that he does it’

In subordinate clauses, if the main verb is in the perfect tense, the auxiliary (which is the finite verb) appears at the end of the clause and the past participle of the main verb appears just before the auxiliary in penultimate position (example 7).

(7) … , dass er es getan hat
           that he it  done  has
     ‘that he has done it’ or ‘that he did it’

Modal verbs in subordinate clauses

Similarly, modal verbs appear in subordinate clauses at the end, and the infinitive of the main verb appears in penultimate position (example 8).

(8) … , dass er es tun kann
           that he it  do  can   
          ‘that he can do it’

Now let’s look at the equivalent of example 8 in the perfect tense. The auxiliary hat (‘has’) appears in antepenultimate (3rd to last) position, the infinitive of the main verb tun (do’) appears in penultimate position and the infinitive (können) of the modal verb kann goes at the end (example 9). 

(9) … , dass er es hat tun können
           that he it  has do  be.able
          ‘that he could do it’, meaning ‘that he was able to do it’

I haven’t been to find out what the the subordinate clause equivalent of example 5 is. I suspect it would be example 10, but maybe it is example 10a.

(10) … , dass er es kann getan haben
            that he it  can done  have
            ‘that it is possible [that] he has done it / did it’
(10a) … , dass er es getan haben kann
              that  he it  done have can
            ‘that it is possible [that] he has done it / did it’

Table 2 summarises the positions of the finite verb, auxiliary and modal in subordinate clauses. The items shown there are as in table 1, as well as C (complementiser = subordinating conjunction (eg dass ‘that’).

  Table 2. Subordinate clauses

The main difference between the word order for main and subordinate clauses lies in the position of the finite verb. The finite verb goes in:

• 2^nd position in main clauses;
• last position in subordinate clauses; but
• 3^rd last position in subordinate clauses containing a sequence of 2 non-finite verbs.

The 2^nd oddity

The 2^nd oddity concerns word order in subordinate clauses containing a sequence of 2 non-finite verbs. Why is it that in these instances the finite verb appears not in last position but in 3^rd last position before the non-finite verbs? Why does example 9 read dass er es hat tun können, rather than dass er es tun können hat? I haven’t come across a good answer to that question.

Other verbs

I’ve focussed in this post on the perfect tense of modal verbs. The same word order also occurs:

• for some other verbs used as quasi-axiliaries, mainly lassen (‘make, allow, let, cause’) and some verbs of perception, such as sehen (‘see’) and hören (‘hear’). Like the modals, these quasi-auxiliaries also use the ‘replacement infinitive’ instead of the past participle.
• in the future tense, which uses the auxiliary werden (‘become’) with the infinitive of the main verb.

According to one source (I’ve lost my note of which one!), this odd word order does not occur if the finite verb is:

• the auxiliary werden (‘become’) when used in the passive; or
• the auxiliary sein (‘be’) used in the perfective. (I’m not sure whether it is even possible for sein to be used at all in forming the perfect of models or of the other quasi-auxiliaries, such as lassen, sehen and hören. So, the word order question might not even arise for sein.)   

Subordinate clauses generally start with a complementiser (or with some other items, such as a relative pronoun). The complementiser is sometimes optional; if it is not present, the finite verb goes in 2^nd position (not at the end), a pattern not illustrated in this post.  

Conclusion

German modals are odd in 2 ways, among others:

• although they have a past participle, in most instances the infinitive is used instead.
• in subordinate clauses, the finite form of modals appears in 3^rd last position, not in last position where all other finite forms go.

I don’t know whether there is any connection between these 2 oddities.

Sources

The Syntax of German, Hubert Haider (2010)

VO-/-OV Base Ordering, Hubert Haider, chapter 15 in The Cambridge Handbook of German Linguistics, edited by Michael T Putnam and B Richard Page (2020) p347-350

Understanding English-German Contrasts, by Ekkehard König and Volker Gast, 4^th edition (2018)

A Student Grammar of German, Paul Stocker (2012)

Further reading

Modality in Syntax, Semantics and Pragmatics, Werner Abraham (2020), including chapter 5 The Perspectival Specifics of Verb Modality in German.

Eisenberg_Smith_Teuber_2002_Ersatzinfinitiv-und-Oberfeld–Ein-großes-Rätsel-der-deutschen-Syntax.pdf