Sequences consisting of alveolar /t,n,s/ + /j/ are realized as pre-palatal [c,ɲ,ʃ] respectively.
/tj/ becomes [c] liedje, weet je
/nj/ becomes [ɲ] franje, kun je
/sj/ becomes [ʃ] pasje, was je
This coalescent assimilation also occurs in sequences like /ns + j/, /nt + j/, /st/ + /j/ and /nst/ + /j/, as in dansje, handje, kistje, kunstje, which are pronounced [ˈdɑɲʃə, ˈhɑɲcə, ˈkɪʃə, ˈkʏɲʃə], with elision of /t/ in the last two words. Palatalization of /t,n,s/ does not occur in the pronunciation of speakers from Limburg and Flanders.
Note that GA /j/ is normally only coalesced to /t͡ʃ,d͡ʒ/ when it occurs initially in a weak syllable, as in get you, did you, situation, education. In sequences like those in not young, that year, /t/ may be glottalized, glottaled or voiced, but /j/ remains fully voiced in all cases. The change of /s/ to /ʃ/ before /j/, as in this year, is somewhat more common, but by no means as regular as in Dutch. In words like menu, onion, a palatal [ɲ] may frequently be heard in rapid and casual speech, but not in more deliberate styles. Note that here again palatalization is the rule in Dutch, where pronunciations like [ˈspɑnjə] for Spanje do not occur even in formal styles. To avoid undesirable palatalization, make a firm alveolar contact for /n/ and /s/, and glottalize, glottal, or voice /t/, making sure that the following /i/ is a fully voiced approximant. For /s/ before /j/, practice the unassimilated form. Here are some examples for you.
not yet ten years Is this you?
courtyard Spaniard misuse (n)
last year in Europe misuse (v)