The Irish language has a long and rich history that spans over two thousand years. It is one of the Celtic language group, that is native to Ireland, and has evolved significantly over time. Today, we see two main forms of Irish: Old Irish and Modern Irish.

Old Irish is the older form of the language, as the name would suggest, though it is not the oldest form of Gaeilge in existence.

It was spoken in Ireland from the 7th or 8th almost to the 10th century. It is a very different language from Modern Irish, and can be difficult for speakers of Modern Irish to understand. Old Irish is characterised by its complex grammatical structure and extensive use of inflections. 

Modern Irish, on the other hand, is the form of the language that is spoken in Ireland today.

It evolved from Old Irish over the course of several centuries, and has undergone many changes in pronunciation, vocabulary, and grammar.

Modern Irish is written using the Roman alphabet, and is much easier for English speakers to learn than Old Irish. It is the official language of the Republic of Ireland, and is spoken by a small but dedicated (and growing!) group of native speakers.

Despite the many differences between Old Irish and Modern Irish, the two forms of the language share a common origin and have a deep cultural connection. Both Old Irish and Modern Irish are an integral part of Ireland's rich cultural heritage, and are an important part of what makes Ireland such a unique and fascinating place.