| Part of speech | unknown part of speech |
|---|
| Singular | Plural | |
|---|---|---|
| Nominative | akustika | akustikaj |
| Accusative | akustikan | akustikajn |
| Czech | akustický; sluchový |
|---|---|
| Dutch | akoestisch |
| English | acoustic; acoustical |
| French | acoustique |
| German | akustisch; Schall‐; Gehör‐; Hör‐ |
| Greek | ακουστικός |
| Hungarian | akusztikai; akusztikus |
| Icelandic | hljóðeðlisfræðlingur |
| Portuguese | acústico |
| West Frisian | akoestysk |