Final answer:
Irregular adjectives in German take the suffix '-en' in the dative singular case to agree with the noun they modify. This is much like how English verbs and nouns can change form with suffixes like '-ed' and '-ess.'
Step-by-step explanation:
The question concerns the morphology of irregular adjectives in the German language, specifically in the dative singular case. These irregular adjectives take the ending -en in the dative singular. For example, a masculine adjective like 'guter' (which means 'good' in English) becomes 'gutem' in the dative singular as in 'mit dem gutem Mann' ('with the good man'). The dative case is used to indicate the indirect object of a verb, and each German adjective must agree in case, number, and gender with the noun it modifies.
Using the provided suffix rules for English as a reference for German, we can observe a similar complexity in the way words change form to convey grammatical information. For instance, in the given English examples, suffixes such as -ed and -ess can change the meaning or grammatical role of the base word. Like in English, German adjectives also undergo changes; however, they are influenced by the grammatical case, gender, and number of the nouns they describe.