Ido/How is Ido different from Esperanto?

Vocabulary
Ido is a modified version of Esperanto with a number of changes designed to make it easier to learn and easier to type.

The first noticable difference between the two languages is that Esperanto has the diacritical marks ĝ, ĥ, ĵ, ŭ, ĉ, and ŝ. These are used in order to adhere to the one letter = one sound rule, but many thought them to be a needless barrier in promoting the language. Ido did away with letters with diacritical marks and instead replaced:
 * ĝ with j (pronounced as in French je and as the 'zh' sound as the 's' in 'pleasure')
 * ĥ with h (the ĥ in Esperanto is pronounced as a gutteral as in Arabic)
 * ĵ with j (same sound as above)
 * ŭ with u
 * ĉ with ch
 * ŝ with sh.
 * j with y

Internationality
The creators of Ido felt that much of Esperanto was either not internationally recognizable, or unnecessarily deformed. Ido aims to fix these with more "international" or "corrected" roots. This can sometimes be at the expense of Esperanto's simplified word building process. Below are some examples.

Affixes
The prefix mal- (creating a word with the exact opposite meaning) in Esperanto is overused as a prefix. It can be inappropriate since it has negative meanings in many languages.

The primary Ido grammar book states that one reason for the adoption of the Latin-based sinistra for "left" instead of maldextra (mal- plus the word dextra, or dekstra for "right") is that often only the last one or two syllables can be heard when shouting commands.

Ido does not assume male gender in a word.

Personal names
As stated above, most European given names have Esperanto equivalents: "John" is Johano, "Alexander" is Aleksandro, etc. Because some cultures place the surname first before the given name and others last after it, it is the practice of some Esperanto writers to give surnames in all capital letters, although it is unusual to find this in publications. "John Smith" would thus be rendered "John SMITH" or "Johano SMITH" in the first mention. Most non-Western names do not have equivalents and are rendered as close as possible in Esperanto orthography.

Ido, on the other hand, simply leaves the names as is; "John Smith" would be "John Smith" in Ido. Names from languages with non-Latin scripts are rendered as phonetically as possible. Ido does not capitalize surnames.

Place names
Most countries have their own names in Esperanto. The system of derivation, though, is sometimes complex. In Old World nations, where the country is named after an ethnic group, the main root means a person of that group: anglo is an Englishman, franco is a Frenchman. Originally, names of nations were created by the addition of the suffix -ujo (container), hence England and France would be rendered Anglujo and Francujo respectively (literally, "a container full of Englishmen/Frenchmen"). More recently, Esperanto has adopted -io as the national suffix, thus creating names more inline with standard international practice (and less odd-looking): Anglio, Francio.

In the New World, where citizens are named for their nation, the name of the nation is the main word, and its inhabitants are derived from that: Kanado ("Canada"), kanadano ("Canadian").

Names of cities may or may not have an Esperanto equivalent: Londono for London, Nov-Jorko for New York. Place names which lack wide-spread recognition, or which would be mangled beyond recognition usually remain in their native form: Cannes is usually rendered as "Cannes".

In Ido, country names must conform to the language's orthography but otherwise are left unchanged: Europa, Peru, Amerika. City names are treated as foreign words (London), except when part of the name itself is a regular noun or adjective: Nov-York (Nov for nova, or "new", but the place name York is not changed as in Esperanto "Nov-Jorko"). This is not a hard and fast rule, however, and New York is also acceptable, similar to writing Köln for the city of Cologne in Germany. South Carolina becomes Sud-Karolina, much in the same way that a river called the "Schwarz River" is not transcribed as the "Black River" in English even though schwarz is the German word for black. However, less well-known place names are generally left alone, so a small town by the name of "Battle River" for example would be written the same way, and not transcribed as "Batalio-rivero". This is because transcribing a little-known place name would make it nearly impossible to find in the original language.