Old-fashioned letter style. Ideas: presented politely & carefully. Fixed expressions. Latin-origin words. Impersonal language. Grammar & punctuation: important.
Professional s style. Language: simple & direct. Short sentences & some contractions. More personal language. Grammar & punctuation: important.
Personal s style. Language similar to speech. Everyday words. Contractions & abbreviations. Grammar & punctuation: less important.
FORMAL: – It is necessary for me to obtain this information at your earliest convenience. NEUTRAL – I would really appreciate it if you could send me the information as soon as possible. INFORMAL – Pls send me the info ASAP.