How English speakers say I, II, III...chord?

[coke]

I am not an English native speaker.
I want to know how English native speakers say I/II/III/etc. in conversation.
Is it "I chord"="one chord" or "first chord" or "tonic chord" or something?
Then "Im" is "one minor chord"? "I7" is "one seventh"?

I don't know how to converse with an English speaker so I really want to know. Thank you so much.

[keypeg]

I think my teacher refers to "one chord".  It doesn't come up often, but I do remember in conversation on occasion I have asked him which kind of "one" he meant when he only said "one" and assumed I knew which through context (I can be slow at times).

[iansinclair]

I would be more inclined to think of -- and use -- the terms tonic, dominant and subdominant... avoids confusion.

[chopinlover01]

Most of the time, theorists use the number names. Ie one, two chord, etc. This is because using words gets very confusing very quickly; if, for instance, you're in the key of C, and you see the following progression:

C - A - Dmin - G7

You'll notice quickly that the A major triad is not from the home key of C major, but a secondary dominant to the key of D minor (derived either as the A major triad, or in more complicated modal theory, derived from building triads off of the harmonic minor scale). In any case, when you have chords like these, instead of saying "the major submediant of the supertonic", you say "the five of two", or "the five borrowed from the two chord", or something like that. Words don't really do the technical terms justice here.

[klavieronin]

This is how I've always heard people talk about chords and how I talk about chords;

For basic triads; "chord one", "chord two", "chord three" etc. but sometimes "tonic chord", "dominant chord", etc. are used, particularly if you are talking about the chords in a more general sense rather than a specific example but generally these are interchangeable.

For seventh, ninth, eleventh chords, etc.; "chord one seven" (or just "one seven"), "four seven", "two nine", "five eleven", etc.

For secondary or applied dominants; "five of five", "five of two".

For things like mixture chords or altered chords you might use terms like; "minor five", "two sharp three", "one add nine", etc.

[Bob]

Basically the same as others.  I think people might refer to I as the tonic more than one chord.  IV and V might be "four" and "five" chords as much as subdominant and dominant.

[coke]

Thanks, everyone!

[quantum]

When referring to a single chord or a very short sequence, the functional name can be used:
"The 'one' chord in bar 67", "The progression from dominant to submediant in bar 12."

However for longer progressions this gets cumbersome:
Say: I, I⁶, IV, ii⁶, V^64-53, I
Could be: "One, one-six, four, two-six, five six-four, five-three, one."

If you are using chords or sequences that have a name, you could also just use the name if it is easier to identify:
Examples: Neapolitan 6th, Italian 6th, German 6th, French 6th, horn call.

If you are talking in general of theoretical applications, you could omit saying the Roman numeral and only refer to the inversion:
"This passage is an example of 'six-three' chord techniques"
"Insert a cadential 'six-four' at the cadence in bar 16"

When talking about chord quality types you could say:
"Seventh chord, ninth chord, half-diminished chord"

In contrast, scale degrees for individual notes or melodies, often notated with a ^ over the Arabic numeral can be differentiated by pronouncing:
"First degree, second degree, third degree" etc.
Or use their names:
"Tonic, supertonic, mediant" etc.