This is a history that perhaps should remain unwritten. If you're easily offended, you probably don't want to read it. And so I'll keep it brief. Bush may not appreciate the original source of the popularity of the phrase...which could not help but resonate for the many members of the British and US sub- and counter-cultures listening to him. And laughing.
The exact phrase "read my lips" first appears, in the documentation available to me, in the late 19th century. At that time, it was associated with teaching deaf children. So, this from an 1893 volume titled Summer Meetings: American Association to Promote Teaching of the Deaf is the first instance I could glean from Google Books:
He gave me three girls to teach for a week; one of them was born deaf and dumb. I taught them to say some sentences and to read my lips in learning them.
Isolated appearances with reference to teaching the deaf continue through the first six decades of the twentieth century, and beyond, in books, journals and newspapers.
Then comes the boom in popularity, partially sponsored by a counter-culture film called The Rocky Horror Picture Show, starring Tim Curry et al. A Wikipedia article calls it "the longest-running release in film history". Let's just say it was popular. Very popular among select groups. Lips, in a variety of guises, feature large in the film. For example, a description of the film intro from a transcription:
{ chant "Lips...lips...lips..." and cheer when they appear }
{ "A long long time ago, in a galaxy far, far away,
God said: 'Let there be lips,' (let's fuck) and there were.
And they were good. and the lips said 'thank you'. Sing!"
or "And on the eighth day God made lips.
And there were lips, and they were good lips,
and they gave good head"
....
(From the script archives at Zenin's Rocky Horror Picture Show Archive!!!.)
When, in 1978, the star of The Rocky Horror Picture Show, Tim Curry, released his first solo album (an 'album' was at that time the medium for recorded music), he titled the album Read My Lips. The title traded heavily on the subtext arising from the artist's having been the star of the film. Its success among the sub- and counter-culture groups that made up the fan base of The Rocky Horror Picture Show was guaranteed. It remains a significant release for many fans, as an article at Why It Matters from September, 2013, testifies:
... Curry recorded some kickass albums for A&M Records.
Read My Lips was the first of the three, released in 1978 when Rocky Horror mania was at its peak. I was one of those Rocky Horror fans, which is why I’m writing this while wearing a corset and garter.
Be all that as it may, which it might or might not, because although William Saffire in a September, 1988 Washington Post article titled "ON LANGUAGE; Read My Lips", seems to contradict it by quoting Tim Curry, he also confirms the origin is "rooted in rock music":
Read my lips is rooted in rock music. In 1978, the actor-singer Tim Curry gave that name to an album of songs written by others (though it did not include a song with that title copyrighted in 1957 by Joe Greene).
Reached in Washington, where he is appearing in ''Me and My Girl,'' Mr. Curry recalled that he got the phrase from an Italian-American recording engineer: ''I would say to him, 'We got it that time,' and he would say, 'Read my lips - we didn't.' That phrase arrested me, and I thought it would make an arresting album title. Be a good name for Mick Jagger's autobiography, come to think of it.''
Saffire goes on to complete his clandestine apologetics--a transparent, but apparently successful effort at damage control--for Bush's use by tracing perhaps more direct and less compromising influences. Notice that Saffire chooses to characterize Bush's use as a "stern intensifier", rather than sarcastic:
- songwriters, including the pair that wrote the song recorded by Melba Moore;
- "sports figures snapped up the stern intensifier. The phrase appeared as a nickname suggesting emphasis in orders by a football coach -Mike (Read My Lips) Ditka" (op. cit.);
- the name of a race horse;
- a use by a heavyweight boxer in announcing how he would announce his retirement;
- a use by a White House aide insisting the hostages released by Iran be brought home in planes marked "United States of America";
- a 1987 use by Senator Albert Gore while questioning the Under Secretary of Defense about missile funding, during which Gore managed a surprising twist by putting the words into the mouth of the Under Secretary: '"You're saying, 'Read my lips, cut the money'." for the Midgetman, said Senator Gore. "Your message is clear."' (op. cit.).
Best Answer
I think Yes, let's is a perfectly good answer here (that is, I don't believe it is any less "formal" than the use of the word "shall" by the questioner).
But, to avoid using that phrase, I think something like Absolutely would work (though it is a bit emphatic). You could also say That would be great or I would like that if the affirmative answer depends at all on your own opinion of the idea of chatting.