Most differences are in the lowercase letters. The one letter that is most often different in different alphabets is the lowercase g.
• Shown on the above image is the variety that exists in twenty-four typefaces.
• Note the subtle difference in the Garamond, Jenson, and Times Roman
• Also note the Caslon 540 and Caslon old face: they are not the same, but the casual observer might think that they are.
Characteristics of other letters are also shown to give the reader some clues for further recognition.There are three basic groups of sans serif types:
1. grotesque or gothic
Grotesque (often shortened to Grot) and Gothic are 19th century designs with nearly uniform proportions See Helvetica and News Gothic. Sans serif types, like Futura, are very mechanical. Humanist designs follow classic proportion of Roman Capitals and Renaissance lowercase. Many have thick/thin stress and calligraphical elements. An example is Optima.
Here are many varieties of lowercase t. The tops are flats or curved or pointed, and the bottoms are either flat or curved, parts to be observed in identifying a typeface style.
Observe the variations on the letter e set in different typefaces. The cloister has an angled crossbar. Baskerville blends gracefully from thick to thin. The Garamond has a freehand look, with a high loop and crossbar. The Bodoni changes abruptly from thick to thin and has a straight curve. The curve of Caslon 540 has weight towards the bottom.
Here are five varieties of serifs on the letter u. Serifs are not the only way to identify type, but you will become more sensitive to such subtle changes as these when developing a better understanding of letter forms.
In any alphabet more differences in form will be found in these letters than in any others
Hope this post will help you in understanding different typeface types.