The bondedness of a binary construction is the tightness of its internal syntagmatic relation, its syntagmatic cohesion. It increases with grammaticalization, becoming tighter. Examples clearly displaying this aspect of grammaticalization include the following:

• The Romance synthetic future clearly shows a series of phases of coalescence. In the initial phase, the construction in question is a free syntactic construction in which the non-finite full verb is a constituent beside the verb form of habere ‘have’, still a full verb at that point. In the next phase, the auxiliary follows the infinitive immediately and then becomes clitic on it. In the final phase, it becomes a conjugation suffix.
• The Chinese aspect markers le and zhe start out as full verbs which enjoy the independence of this category. When they are grammaticalized to aspect markers, they become clause-final enclitic particles and even suffixes on a full verb.
• The English auxiliaries and modal verbs be, have and will start out as words. With grammaticalization, they become clitic on the subject NP that they follow. If this is a personal pronoun, they get phonologically reduced: The singular forms of be are then /m, ə, z/; the forms of have are /v, v, z/; and the form will reduces to /l/. These attach enclitically to the preceding pronoun, forming one phonological word with it.
• The definite article of the Romance and Germanic languages starts out as an independent determiner. In its fixed position, it regularly follows directly the preposition if its NP depends on one. Then it becomes clitic to this preposition. With the Spanish prepositions a dative and de genitive and the definite article el (DEF.M.SG), this produces word forms like al (DAT:DEF.M.SG) ‘to the’ and del (GEN:DEF.M.SG) ‘of the’. This process goes even further in French, where the corresponding forms are au /o/ and du /dy/, with the definite article being merged completely into a portmanteau morph.