The (a)-examples in (25) show that proper nouns do not normally allow any form of modification aimed at restricting the number of potential referents: (25a) is acceptable but only when the attributive adjective is used non-restrictively, i.e. to provide additional information about the referent of the noun phrase; (25a') becomes perfectly acceptable when the relative clause is preceded by an intonation break, which is the landmark of the non-restrictive use of such clauses. Example (25b) shows that if the proper noun itself contains a (restrictive) modifier, the latter cannot be omitted without the noun phrase losing its status of proper noun.

The examples in (26) allow a restrictive modifier when there is more than one accessible referent in the context that can be referred to by the same proper noun or, in other words, when unique identification is not possible on the basis of the proper noun alone.

The examples in (27a&b) show that proper nouns cannot be pluralized unless the proper noun phrase itself is formally plural; example (27b') shows that in the latter case the singular is not available (at least not as a proper noun).

This difference in syntactic behavior between common nouns and proper nouns can again be explained by the fact that proper nouns are supposed to refer “uniquely” within a given context, providing the addressee with sufficient information to identify the intended referent. If the proper noun fails in this respect, as in (28), pluralization becomes possible.

Unlike common nouns, proper nouns are not normally acceptable with an article in standard Dutch. Nor can they be used with a demonstrative pronoun or other determiner; cf. (29). Note, however, that in certain southern dialects of Dutch, the use of the definite article or a possessive pronoun is acceptable with proper nouns referring to persons: de/onze Jan.

However, articles are used when they can be considered as part of the proper noun (sometimes written with a capital letter; cf. De Volkskrant). Example (30b) shows that in such cases the use of other determiners is still prohibited.

The examples in (31) contain the proper nouns Jansen and Italië and show that restrictive modification requires the addition of a determiner: singular proper nouns denoting an animate object take the non-neuter definite article de, as in (31a), while singular proper nouns denoting a geographical name take the neuter definite article het, as in (31b).

When an article is used in combination with proper nouns that themselves already contain a definite article, such as De Volkskrant in the (a)-examples in (32), the latter is typically left out. However, this is not the case when the article is an old case form such as den in example (32b), which suggests that present-day speakers no longer recognize these elements as articles.

Example (26c) has shown that the names of the days of the week can also be used in combination with the definite article and an identifying modifier. If we are referring to a specific day close to the moment of speech, the determiner is usually omitted, even if the noun is modified. However, if the intended day is more remote, the definite article is usually used. This is shown in (33).

Indefinite articles are also possible; the noun phrase can then refer to either a specific (but not further identified) day, as in (34a), or a non-specific one, as in (34b).

Proper nouns referring to seasons and names of the months are more restricted with respect to the determiner. The examples in (35) show that the names of the seasons must be preceded by a definite determiner, whether or not a restrictive modifier is present.

The examples in (36), on the other hand, show that the names of the months cannot be preceded by a definite determiner, again regardless of whether a restrictive modifier is present or not. These examples also show that, for unclear reasons, it is not possible to modify januari by means of van 1963; the proper noun is immediately followed by the year or (more formally) by a van-PP of the form van het jaar 1963.

The examples in (37) show that neither the names of seasons nor the names of months can be preceded by an indefinite article, again regardless of whether or not a restrictive modifier is present.

Finally, proper nouns can co-occur with the demonstrative determiner die in the informal expressions given in example (38), which are used for expressing surprise, usually combined with a touch of admiration (“who would have thought it!”) or pity (“poor fellow/girl”). Surprisingly, die is the only form available, even when it precedes a [+neuter] noun like the diminutive in (38b); cf. Section 19.2.3.2, sub IIE, for further discussion.