Søndergaard used his time in Italy as the basis for two of his works, Vinci, Senere and Processen og det halve kongerige.
[5] These themes are expanded in the collection Et skridt i den rigtige retning, (A step in the right direction, 2005), which explores the relation between walking and poetry.
[11] Søndergaards Ordapotek (Wordpharmacy) is a concrete poetical work, which equates the structure of language with pharmaceutical products.
This poetic experiment consists of ten boxes of medicines, one for each word class, such as verbs, nouns or adverb.
[12][13] Søndergaard’s explorations of the various collisions between meaning and materiality has resulted in extra-linguistic works that span sound art, artists books, asemic writing[14] strategies and performance.
His artistic practice unfolds around explorations and challenges of what poetry can be and is, and how it can subsist in the breaches and connections between signs and things.