Mark J. Reed wrote:

>Singular/plural and informal/formal distinctions in the second person
>merged and conflated in a wide variety of ways in I-E languages.
>Usually there's a cycle: what used to be considered form X becomes
>form Y, necessitating a new coinage to be the new form X,
>then something gets abbreviated in some way, etc.
>Spanish originally had "tú" in the singular and "vos" in the plural.
>Then "vos" came to be used as a polite singular.  This required a new
>coinage to take the place of the familiar plural - "vos otros" (you
>others), which was contracted to the single word "vosotros".
>But over time "vos" lost much of its air of formality, so yet another
>new coinage became the polite singular: "vuestra merced", literally
>"your grace", which had a built-in plural form (vuestras mercedes, "your
>graces").  These phrases were contracted to "usted" and "ustedes".
>Meanwhile, people went back to using either tú or vos, depending on
>dialect, as the familiar singular.
>But the process didn't stop there.  In most of the Spanish-speaking
>world the plural "ustedes" has completely lost its formaility,
>supplanting "vosotros" as the familiar plural form.  This may mean that
>there will come a new coinage to become the new "really formal" plural
>in those areas, but cultural factors will likely prevent that from
>happening; there seems to be a general tendency toward familiarization
>and dropping of the familiar/polite distinction, not just in Spanish but
>many languages and cultures.
>Anyway, the result in current Spanish is the following locale-dependent
>                Sing            Plural
>Familiar        tú or vos       vos or vosotros or ustedes
>Polite          usted           ustedes

  I've noticed people here in Peru mixing the formal subject usted with
informal object/genitive forms  te, ti, tu rather than the formal forms
le, usted, su.

  Re familarisation I understand the change is usually from to formal
forms to the informal forms. Are there any languages, other than
English, where the change is/was from informal forms to formal forms?

David Barrow