Several symbols had too many meanings to permit clarity.
Therefore, symbols were put together to indicate both the sound and the meaning of a compound.
Certain signs to indicate names of gods, countries, cities, vessels, birds, trees, etc., are known as determinatives and were the Sumerian signs of the terms in question, added as a guide for the reader.
Proper names continued to be usually written in purely "logographic" fashion.
They used either geometrical patterns or another cuneiform sign.
As time went by, the cuneiform got very complex and the distinction between a pictogram and syllabogram became vague.
Words that sounded alike would have different signs; for instance the syllable "gu" had fourteen different symbols.
When the words had similar meaning but very different sounds they were written with the same symbol.
Cuneiform tablets could be fired in kilns to provide a permanent record, or they could be recycled if permanence was not needed.
Many of the clay tablets found by archaeologists were preserved because they were fired when attacking armies burned the building in which they were kept.
The system consists of a combination of logophonetic, consonantal alphabetic and syllabic signs.
The original Sumerian script was adapted for the writing of the Semitic Akkadian (Assyrian/Babylonian), Eblaite and Amorite languages, the language isolate Elamite and for the language isolate Hattic, Hurrian and Urartian languages, as well as Indo-European languages Hittite and Luwian, and it inspired the later Semitic Ugaritic alphabet as well as Old Persian cuneiform.
Cuneiform writing was gradually replaced by the Phoenician alphabet during the Neo-Assyrian Empire (911–612 BC).