Prof. Haiping Long, Sun Yat-Sen University, China:
A sentence adverbial (SA) indicates the attitudes of the speaker and/or speaker-hearer interaction. From the perspective of language interaction one may specify three positions for an SA, i.e., a clause-initial position (CI-position; e.g., admittedly the motive of the law was good), a clause-medial position between the subject and the main predicate (CM-position; e.g., he is evidently right), and occasionally a clause-final position (e.g., they may have been sent to London possibly).
Previous studies generally focus on SAs developed in a CI-position and have largely neglected SAs developed in a CM-position. The development of some SAs in English, Galician, German, Japanese, and Tibetan, together with the systematic development of mono-syllabic SAs throughout the history of Chinese (see the following) indicate that the CM-position is also a prototypical position for the development of SAs.
(1) Huángfà chuítiáo, bìng yírán zìlè. (黄发垂髫，并怡然自乐。)
‘The elderly and the children, they all feel contented and happy.’ (365 CE – 427 CE, Peach Blossom Spring (《桃花源记》))
(2) Zhāngshēng bìng bùcéng rénjiā zuò nǚxù. (张生并不曾人家做女婿。)
‘Mr. Zhang on the contrary never married into and lived with his wife’s family.’ (1295 CE – 1307 CE, Romance of the West Chamber, Vol. V, Act IV (《西厢记·第五本·第四折》))
A conventionalized SA developed in a CI-position may later develop to occupy a CM-position (e.g., the motive of the law was admittedly good), and a conventionalized SA developed in a CM-position may later develop to occupy a CI-position (e.g., evidently he is right). In both cases, the change is not gradual but abrupt, and filling the gap is the primary driving force for the change to take place. I also re-examine the commonly accepted view that circumstance adverbials develop into SAs only in a CI-position.