[OP u for IE ṛ before n is not a phonetic development, since there are contrary examples. The instances of u are all in forms of kar- ‘make, do’, where they have been induced by *tunautiy ‘is strong’ and *çunautiy ‘hears’, for which there is evidence in Iranian.]

[The indefinite-relative-interrogative stem recently recognized for Hittite is not mo- as has been thought but smo-, i.e. IE sem- sm-, already known as forming indefinites and the numeral ‘one’. From it are to be derived Hitt. sanas (cf. Gr. μόνος) and sa-; masis and masiyanki; -ma (perhaps seen in namma, nasma, and imma), man, and mahhan, and their cognates, Skt. sma, Gr. μά, μέν, and μā́ν; Lat. -met and the particle *sme in case-forms of Skt. pronouns; Gr. μ∊τά and μέχρι; perhaps Gr. μή. The collocation μἐν . . . δέ is a combination of relative-demonstrative like ut . . . ita, etc.; indeed, sem- smo- in its uses and derivatives shows frequent parallels to kwo-.]

[Latin -ks- is represented in standard Italian by two ‘popular’ developments: -ss- and -šš- (saxum > sasso; coxa > coscia). Examination of the geographical distribution of words whose Latin etyma contained -ks- shows that the -ss- development was originally characteristic of central and southern Italy (hence also of Tuscan and the standard language), as well as of northeastern Italy with simplification to -s-; and that palatalization of -ks- to -s- and -š- was originally characteristic of northwestern Italy, whence words with -š- were borrowed into standard Italian and thence spread elsewhere in Italy.]

[The IE dh-determinative effects a consistent modification of meaning in Germanic. Basically this is in nouns formed from transitive roots a past passive modification, in nouns formed from intransitive roots and in verbs a modification caused by previous action.]