The words in each set were linked together by their meaning but showed their different types, those with the Normal, those with the Weak, and those with the Deflected form of root. These types are called Grades of Ablaut. Ablaut is a convenient German name (literally: ‘variation of sound’) for the connexion between the Normal forms on the one hand and the Weak and Deflected forms on the other.
§ 77. Now these new forms, though they had arisen by unconscious phonetic changes, had come to be associated with special kinds of meaning, e.g.
| Normal. | Weak. | Deflected. |
| I.Eu. *ten-iō ‘I stretch’ | *tn̥tós ‘stretched’ | *tétone ‘he has stretched.’ |
| *tonós ‘a stretching.’ | ||
| Gr. τείνω | τατός | τέτονε, τόνος. |
| Lat. tendo, tenor | tentus | |
| I.Eu. *lei̯q-ō ‘I leave’ | *éliqom ‘I left’ | *leloi̯qe ‘he has left.’ |
| *liq-tós ‘left’ | *loi̯qós ‘remaining.’ | |
| Gr. λείπω | ἔ‐λιπον | λέλοιπα, λοιπός. |
| Lat. | re-lic-tus |
Thus the Weak form came to be felt as proper to the partc. in -tos and the Deflected form as proper to the Perfect Active (in the Singular) and to derived Nouns or Adjectives of what we call the First and Second Declensions; compare also the examples in §§ 71, 73 and 74.
Hence it is true to say that though the phonetic changes which had first produced the Grades of Ablaut
