Declension table of ?yauvanastha

Neuter	Singular	Dual	Plural
Nominative	yauvanastham	yauvanasthe	yauvanasthāni
Vocative	yauvanastha	yauvanasthe	yauvanasthāni
Accusative	yauvanastham	yauvanasthe	yauvanasthāni
Instrumental	yauvanasthena	yauvanasthābhyām	yauvanasthaiḥ
Dative	yauvanasthāya	yauvanasthābhyām	yauvanasthebhyaḥ
Ablative	yauvanasthāt	yauvanasthābhyām	yauvanasthebhyaḥ
Genitive	yauvanasthasya	yauvanasthayoḥ	yauvanasthānām
Locative	yauvanasthe	yauvanasthayoḥ	yauvanastheṣu

Compound yauvanastha -

Adverb -yauvanastham -yauvanasthāt